White gold filled with a black dial sporting 3 diamonds and white gold indices. 17J movement. No notch in the dial indicating a refinish. I find this casing in solid yellow gold for the Envoy and Ellsworth - 21J with no diamonds. Nothing in gold filled or white. I'm stumped, but believe it's correct as seen. My best guess is Beau Brummell. Maybe somebody else will find an ad or linebook entry I missed.
In reply to Sorry but nothing is jumping… by Geoff Baker
Structurally similar style wise to Beau Brummell "O" and "P" from 1957. Also the "W" from 1958. We have yet to identify variant "N" and potentially "NN" which very likely shared the same rectangular (as opposed to round) case, 17J movement and dial style. Dial is a match to the "P" and "W", including text and subseconds white print; with the exception of the diamond mount shape. I'm not suggesting subject watch should be christened an "N" without documentation, but there looks to me to be enough similarities to call it a Beau.
1958 Bulova Beau Brummel price list
The "O", "P" and "W" all have 3 diamonds in a 10K Gold Filled case and are each listed at either $89.50 (O,P) or $115 (W).
I think it's safe to rule out the "N" as that is listed as $175, unless there are two versions of the "N", Filled and Solid - See "A" and "B" models below that look to have 2 price points suggesting a difference in gold content. Although the below listing only shows the one "N" variant, which I suspect is solid gold.
All in all I have to agree with Unknown (but likely a BB). Note that there are 2 x "O" variants listed at the same price point.