January 07, 2011, 09:45
Roger StephensGruen Watch Serial Numbers
case Gruen  VERI-THIN cased and timed in U.S.A. Wadsworth 10k gold filled G337056 and a S under that
January 07, 2011, 10:12
Ernie LogaRoger:
Thanks for posting the photo. nice looking watch.
January 07, 2011, 10:17
Ernie LogaHere is a photo of one I just got on Ebay. Inside the back cover is engraved, George F. Moultor, Xmas 1922. It is an octagon case, White Gold filled.
January 07, 2011, 10:18
Ernie LogaHere is a photo of the movement with serial number 603236.
February 15, 2011, 09:00
Mark CrossThe semi-thin 12s 15j I got for Christmas has the number 748 (model or serial number?) and 'Gruen Guild' on one of the plates. Housed in a solid bow Gruen marked gold filled case. 
Chris Abell currently has it, so I can't offer any more info off the movement than that right now.
Any clue what year this may have been made? I'm guessing mid '20's, as it has a dial EXACTLY like my 1926 Elgin 17j 12s.
Regards! Mark
February 15, 2011, 16:02
Ernie LogaMark:
I don't know when they started using the Gruen Guild name for sure.The earliest Gruen Guild ad I have is from 1922. The newest is 1934. So all we know for sure is they used it from 1922 to 1934.
I believe the 748 is a grade or caliber   designation. I have also collected numbers 650, 716, 756, 758, and 754. All of them were associated with a Gruen Guild watch.
Ernie
February 15, 2011, 16:22
Mark CrossVery good. Thanks! 
I'll have to ask Chris to keep his eyes open for a serial number when he gives it it's COA.
Regards! Mark
February 15, 2011, 17:20
Ernie LogaHere is a summary of the Names used in Gruen Ad campaign from 1915 through 1970:
1915	Gruen Veri Thin Watch
1915	Gruen Watch Manufacturing Co.
1916	Gruen Watch MFG. CO.
1918	Gruen Guild Watches
1919	Gruen Guild Watches
1920	Gruen Guild Watches
1922	Gruen Guild Watches
1923	Gruen Guild Watches
1924	Gruen Watch Makers Guild
1925	Gruen Guild Watches
1925	Gruen Guild Watches
1926	Gruen Guild Watches
1926	Gruen Watch Makers Guild
1928	Gruen Guild Watches
1928	Gruen Watch Makers Guild
1929	Gruen Guild Watches
1929	Gruen Watch Makers Guild
1933	Gruen Guild Watches
1934	Gruen Guild Watches
1936	Gruen The Precision Watch
1937	The Gruen Watch Co.
1937	Gruen The Precision Watch
1940	Gruen The Precision Watch
1941	Gruen The Precision Watch
1942	Gruen The Precision Watch
1943	Gruen The Precision Watch
1944	Gruen The Precision Watch
1946	Gruen The Precision Watch
1946	Gruen The Precision Watch
1947	Gruen The Precision Watch
1948	Gruen The Precision Watch
1949	Gruen The Precision Watch
1950	Gruen The Precision Watch
1954	Gruen The Precision Watch
1955	Gruen The Precision Watch
1959	Gruen The Precision Watch
1970	The Gruen Watch Co.
It appears that they used Gruen Guild Watches and Gruen Watch Makers Guild interchangeably. I also uncovered an ad that used Gruen Guild Watches in 1918.
February 17, 2011, 11:12
Bill CarlsonHi Ernie, I'll put these Gruen pictures on here if they will be of any help.
February 17, 2011, 15:33
Ernie LogaThanks Bill, yours is the first wristwatch I have recorded. Nice looking watch!
February 17, 2011, 15:35
Ernie LogaHere is an updated list of Serial Numbers:
131	Gruen 50th Anniversary
474	Gruen Watch Company
21933	Gruen Guild
33859	Gruen Guild
42421	Gruen Watch Company
45256	Gruen Guild
47386	Gruen Guild
62000	D. Gruen & son
62001	D Gruen & Son
62609	D Gruen & Son
63710	D. Gruen & Son's
65077	Gruen Guild
66694	Gruen Guild
101760	Gruen Guild
126655	Gruen Watch Company
127674	D Gruen & Son
128303	Gruen Guild
128930	Gruen with Logo
129572	D Gruen & Son
137547	D Gruen & Son
138144	D Gruen & Son
140167	D Gruen & Son
313471	Gruen Precision
457723	Gruen Watch Company
461232	Gruen Watch Company
468750	Gruen Watch Company
469691	Gruen Watch Company
472682	Gruen Watch Company
484309	Gruen Watch Company
484867	Gruen Watch Company
496058	Gruen Watch Company
506208	Gruen Watch Company
517242	Gruen Watch Company
517295	Gruen Watch Company
518969	Gruen Watch Company
519526	Gruen Watch Company
521156	Gruen Watch Company
528203	Gruen Watch Company
530065	Gruen Watch Company
541713	Gruen Watch Company
544818	Gruen Watch Company
547011	Gruen Watch Company
549973	Gruen Watch Company
552690	Gruen Watch Company
555328	Gruen Watch Company
556841	Gruen Watch Company
556847	Gruen Watch Company
561747	Gruen Watch Company
603236	Gruen Watch Company
605166	Gruen Watch Company
605896	Gruen Watch Company
632273	D Gruen & Son
711343	Gruen Guild
711516	Gruen Guild
850685	Gruen Watch Company
5577783	Gruen Watch Company
2-194135	Gruen Watch Company
2-219954	Gruen Watch Company
2-327612	Gruen Watch Company
2-328087	Gruen Watch Company
4-121626	Gruen Watch Company
4-121626	Gruen Watch Company
4-125142	Gruen Watch Company
4-132618	Gruen Watch Company
4-133613	Gruen Watch Company
4-140344	Gruen Watch Company
4-151492	Gruen Watch Company
4-185332	Gruen Watch Company
4-230555	Gruen Watch Company
4-232560	Gruen Watch Company
4-233057	Gruen Watch Company
No Number	Gruen
No Number	Gruen Guild
No Number	Gruen Guild
February 19, 2011, 11:34
Vincent Pullara, Jr.Ernie,
Here are 3 of my Gruens
Gruen Veri-thin 17j Mvt. #4-134013
Gruen Veri-thin 17j Mvt. #4-187958
Gruen VeriThin  19J Mvt. 475602
Vince
February 21, 2011, 23:43
Ernie LogaThank you Vince. Your watches are entered into my data. Do you have photo images to post?
Ernie
February 10, 2012, 20:36
Michael BarnettI know this is an old message, but with Gruens decades can go by before breakthroughs happen.
On the GruenWristwatches.com forum, we've just posted one family of calibers that has (hopefully) been decoded. The families are of the 405, 420 & 425 calibers.
You can find the post here:
http://forum.gruenwristwatches...wtopic.php?f=6&t=963I hope folks that are registered members of the forum have comments, corrections, or additions. If you're not a member, please sign up, it's free of course.
December 23, 2012, 20:18
Roger StephensGruen Watch Co.15Jewels s/n 4-121626 Veri-Thin
July 28, 2013, 02:18
Kenneth EdmondsonThank you so much for your work here.
1) I have a Gruen Verithin (no hyphen) Precision, 17 jewels, Adjusted, Temperature. V4
Serial number: 539112
Case is a Wadsworth G081773 14k Goldfilled
Pentagon with pentagon cut crystal.
2) Gruen Verithin (no hyphen)
On movement: Gruen Watch Co, Verithin, 17 Jewels, 5 positions, Temperature, adjusted
Serial number: 484975
No case
Kenneth
September 10, 2013, 04:55
Michael BarnettI recently figured out that this post was here.  The post to pages on my site have changed. The one I posted on  Feb 10, 2012 is now located off the main page.
The main GruenWristwatches.com site is:
http://www.GruenWristwatches.comThe direct link to the serial number page is:
http://www.gruenwristwatches.com/serial-numbers.php