At first glance I thought this was a Watertite watch but I don't thnk it is, the dial is not consistent with Watertite. My next thought was that it might have had a dial swap from one of the ealry-mid forties 'military/service' watches. I searched Unknowns and found one very similar. I also note that Bulova made only a couple round watches in this era but I think this is genuine 1948 and not non-conforming. I'm tagging this one as,
1948 Bulova Unknown
Watch appears to me to possibly be a Seabee like this one:
and this one (inside of case stamped "49")
I'm going with 1948 Seabee
Agree with Seabee
Nice watch and nice match to Seabee Bob. Kind of unique having the date stamp on the inside of the case.
1948 Bulova Seabee