Hi Ken, welcome to myBulova. It looks like you've been afflicted with the dread disease Bulovitis. As you know there is no cure, so enjoy the ride, it's fun.
Not having any markings on the back of the case is unusual. Generally Bulova watches have some markings indicating that the case is a Bulova manufactured case. It is quite common that when a watch case is damaged or worn out that a jeweler or watchmaker will put the movement into an aftermarket (non original) case. In some instances a case from the same brand is available. If we determine that either has occurred we will tag the watch as not original or "Non Conforming'. We aren't saying the watch isn't a nice one or that it has no value, we only stating that the watch can't be assigned a proper Bulova name.
If you could give us a photo of the back and some info from the movement itself we can further determine if that what you have. Perhaps you could have a jeweler or watchmaker open the case back for you. Don't be discouraged in your collecting efforts if that's what we find, we have ALL had it happen to us as well.