I see no reason why we couldn't give this a tentative ID (based on the information we have) for the 21st Century. We know its an official Bulova model (I have 2 NOS packages and crystals as shown above).
Giving it a tentative ID will at least give us something tangible to look for in the adverts as we get new ones.
Similar to Wills 29 Lone Eagle with the later movement. We all know its a 1929 Lone Eagle, regardless of the movement. I think that in situations were a watch case only ever went by one name it shouldn't matter a great deal about the movement, or hands for that matter. Watches that were given multiple names due to a change in date, movement, dial, strap etc, should be treated differently as those aspects do matter to the watch ID.
Back to the subject watch.....whilst I like the idea of making this all about evidence, research and fact, I also like the idea that members of this site (espescially panel members) have a brain of their own and sometimes their thoughts, opinions and theories are on the money. If we have a consensus to tentatively ID this as 21st Century then I'm happy with that, otherwsie if the majority want to assign it to the "Non-Conforming' or 'Unknown' group then that's what we do.
My vote (until such time we have evidence showing otherwise) is a tentative 21st Century.