On a grade 388 model 15 class 98 16 size. I have found that the balance has been changed The elgin part number is 242 BUT the balance has three sets of screws which are in pairs besides the 14 orginal.(screws are all the same)the orginal elgin balance has a even pattern with no pairs. The watch runs.
Did Elgin ever produce such a balance? I see they did for 18 size, but my parts book says no to 16. Would some watchmaker go to the trouble of adding screws?

Walter, some thoughts on your question;

1. If the Balance wheel has matching serial numbers as the movement, the factory would have used as many screws as they determined were needed for the class movement.

2. While replacement wheel #242 is shown with 14 balance weights, it is also only the wheel, less the staff, roller, roller Jewel and Hairspring, and not yet adjusted for temperature either.

Altogether when a watchmaker would use this in a movement, many factors of the final assembly could easily explain more (or less) weights needed to accurately "vibrate" the wheel into proper time accuracy.

David thanks once again for you knowledge and you willingness to share. I am thankfully little wiser for it. I guess one did what you had to do to get things done.

David after understanding I still have a question. would this be a original watch, or would this considered a modified version therefore not a classic example of the origianal. Would this devalue such a piece. And would this also be a subject to criticism.

Walter, Your question has to be qualified by whether or not the Balance wheel has the movement number marked underneath the cross bar. If you are not familiar with Balance wheel removal, do NOT try to look at it.

In general I would reply;

David after understanding I still have a question. would this be a original watch, Yes if the number on the balance wheel so indicates.

(or) would this considered a modified version therefore not a classic example of the origianal.
Replacement Balance wheels are NOT modifications, but rather service items.

Would this devalue such a piece. And would this also be a subject to criticism. No and Not by me (at least) so long as the balance wheel is NOT marked with a different serial number completely.

David, thanks again I do like your logic. the watch does have the correct numbers. I believe that repairs or replacement parts used to keep a watch in service remains a orginal.
thanks again