Case measures 37mm lug to lug x 20mm non inclusive of the Crown using Calipers.
Stainless Steel back.
I'd be willing to bet the case is that of a 1934 Phantom. By 1941, I don't think Bulova was producing the longer tank styles and given the size of the gaps between the bezel and the minute register, especially at 12 and 6:00, I don't think the movement or dial are original to the case.
Interesting observation on the Minute register, but the 'PHANTOM' shown has an identical spacing.
If this style case were not being produced in 1941 from where does the caseback derive?
Stainless Steel is 1940's and it fits perfectly.
The aging around the perimeter of the Dial matches the bezel opening of Case.
I'd say it's original.
Obviously an evolution of the 'PHANTOM' as Greg pointed out, but what's it called?
In reply to Interesting observation on by FifthAvenueRes…