I found 3 models in the ads. A 15 jewel Chesterfield, a 17 jewel Tuxedo and a 21 jewel Douglas. The Tuxedo is very close but has an engraved case in the ad. 
it can actually be a Tuxedo (from 1937, with regard to the case and movement markings), but the bow for chain is altered because it has a completely different shape than the usual Bulovas pocket watch, we have in database another Tuxedo example without engraving
Best I can come up with is an ad from 1943 showing the Tuxedo. Looks like it might be a match but the year difference may be a stretch.
We just don't have enough pocket watch ads to get a feel for the various designs and model names from each year. Tuxedo works for me.
I agree with Ken,
1938 Bulova Tuxedo
Tuxedo works for me. Probably had variants.
1938 Bulova Tuxedo
1938 Bulova Tuxedo.
One of my customers is a Bulova fan, and he brought in a handful of pocket watches. He just wanted to get an idea of which were in better condition so he could decide which ones to service, when to my surprise, he snapped an engraved bezel from one onto another that had had a smooth one.
We tested the interchangeabiity and found that there is indeed a very real risk of mixing up case parts. Interesting, to say the least. I don't remember exactly which models they were, but they were all from around the same time period. I could imagine a damaged case or bezel getting parts donated to it or from it.
I think this might explain why we sometimes see discrepancies in these models.
Flag !!!
arrow on movement and vase s/n start with 7. its a 1937 not a 1938.