1953?Caseback,10K ROLLED GOLD PLATE,BULOVA,L3.Inside caseback BULOVA FIFTH AVE NEW YORK.Signed Bulova crown.Plain dial with very simple markers and dauphine hands.
With two of these of same configeration/date now, it helps rule out or downplay the marriage. Based on the available ads, the break from 21 jewel Ambassadors to 17 jewel is c1952.
I'd go tentative Ambassador on this one (like I did on the other example).
Is subject 10BM movement date coded? I can't see it in the mvnt photo.
When a watch shares many aspects of a series and when that series has a good number of variants it makes sense to tentatively label that watch as part of the series until such time that we come across an advert with a match. The rating system allows for this possibility and watches get updated all the time when new evidence presents itself.
Whilst panel members don't always agree on some model IDs, watches are listed based on the panel majority.