I'm not sure what model it is. The dial appears to be the same as the President OW from previous years but the lugs are a different shape. The Bezel is 10K filled. The non-rotating back is secured with a screw-down ring (not sure when the technical term for this type of back is). I don't know its history and it is currently not working.
Well, I agree that it has 23 Jewels but it appears that the 23 J Bulovas in the mid sixties were called 'Regatta 23'. I find ads but none picturing this exact watch. I'm not a big fan of ID'ing by process of elimination but in this case (pun intended), I might be inclined to do so.
Owner chiming in here. I'm thinking it's an unknown Regatta 23 varient. The two aspects that make me lean towards the Regatta 23 is the shape of the continuous lugs doesn't appear on the 23 but appears on Regatta 23s and the rectangular hour markers seen on other Regatta 23s vs the tapered markers on most 23s. (I'm willing to ignore the marker shape, it could just be a later style but the lug shape seems more convincing.)
Other than advertisements, are there any details that only apply to one of the product lines?
When I get access to a light tent, I'll try getting better pics.
In reply to Owner chiming in here. I'm by Bezalel
To answer your advert question Bezalel, along with a couple price list from various years, it's about all we have.
By the way, the points you make about dial markings and case shape are spot on relative to model ID, along with movement jewel count, it's what we go on. As I said above, I think it might be a Regatta too, I just can't prove it with an ad right now.