I bought a watch online recently (my first bumper). They listed its reference as 2643S.C, and serial as 11162322. When I got it home and opened it up, this serial number was on the caseback. The calibre (351) was numbered 12674441. I was wondering if the difference in numbers had any significance. I had always assumed that one could date a watch (approximately) from the serial number on the calibre - should it be the number on the case back? In date terms it moves me from ca 1947 to ca 1950, not a big difference, but it got me wondering... I would be interested in your views...
The number on the movement is conventionally used as the serial number on most tables you will find. It’s also what Omega uses for Extracts. A good illustration of why photos are better than the word of a seller. Of course it matters little in this case, as the OP points out.