Unknown 1940 Bulova
There is no trace of the stainless back ever being stamped with serial number or other markings.
Original crystal fell off and was lost! It was rectangular with flat sides and a rounded top
The most interesting feature is the guilloche pattern on the dial. I have seen similar dials from the 50s-60s but I found nothing like this in the ads from the 40s. The sides are ridged like many watches from the 50s, so I was surprised when I opened the watch and found the omega date symbol that indicated 1940 for the movement.