1950's Bulova Gents Dress Watch. 
 
For some reason in the 1950's there were companies that recased  Bulova, Elgin and other brands, usually they put something Bulova and underneath thr word movement.
In the case of this watch we suspect that the case is the only thing that's non factory.
 
Taking that away you have a fabulous Bulova watch in great condition, a lovely black  Guilloche style dial and a Bulova 10BC movement under the hood so to speak. 
 
Cosmetically in excellent condition and running well