It has always seemed strange to me That 999E and 999F are easily distinguished as RRWCO but that the other letters seem random.


I see an extremely high correlation after reading the Laser list.


999B would appear to be ORRS, either Ball and Co or Private Label. This appears to be true thruoughout the runs.

999C would appear to be brotherhoods, most likely BRT at least thru the 13 and 14K runs.


999D would appear also to be brotherhoods, most likely BLF at least thru the 13 and 14k runs.

The 28 k run is less clear. All the B's are still ORRS, PL's and Ball and Co, but C's and D's seem to be randomly Brotherhoods in this run.

With decades of switching, it is difficult to say anything with absolute certainty, but I have enough confidence in the mathematical probability of this correlation to state that:

I would definitely want to inspect the bottom of the plates for serial number matches before purchasing a watch that did not conform to my expectations.

The A designation has two BLF's reported but I can offer no conclusion on what signifies it being an A.

BTW , Dr Laser lists the 20,801-21000 999F run as 17J. I believe they are 16J.



happy hunting,
__________________
Bill Kapp