I found this ladies watch on ebay and haven't seen anything like it after searching around. The case is marked M3 but the movement is M0 - Case is 40 micron gold plated. I don't know if the band is original, but it is marked speidel usa and is gold filled.
Hello NumbatNinja, welcome to myBulova. I don't see any matches in our advert dB to your watch, it certainly is in nice condition for it's age and I suspect that the bracelet is original to the watch. It's not uncommon to find a year or two separation between the date code of the movement and the case but we generally date the piece to the newest component. Recognizing the case marking as "Bulova International' I'm curious to know where you live or perhaps more importantly where you found the watch.
1963 Unknown
In reply to Hello NumbatNinja, welcome to by Geoff Baker