Reverend Rob
Posted January 27, 2018 - 11:50pm
Usually the numbers inside these casebacks are reference numbers, but may also include serial numbers.
The reference numbers make it simple for your watchmaker to order parts for the case, and by extension, the movt as well, because the reference number describes the features. (A previous incarnation of this system can be seen with Bulova reference codes) I suspect this watch has a name or maybe even a different number model. As an example, an Omega Speedmaster Professional is the name of the watch, while 3570.50.00 is the reference number that describes the version. Many companies do this, and I suspect Bulova was doing this early on with the International series. Bulova now does this all the time.