Marked L3 on case back as well Movement is marked L2
Hi inky.pendragon, Welcome to mybulova. Your watch is nice, I like the hooded lugs. It appears to be a 1953 Squadron "A" with a replaced dial and hands.
Yellow gold Squadrons had raised gold colored numbers at 12, 3, 9 with "arrowhead" indices at remaining number positions. Like this one:
https://www.mybulova.com/watches/1953-squadron-5805
The 8BA is from the same ebauche as the 8AH, 8AE, etc. that we normally find in the Squadron of this period.
However, the fact that we don't see an example with another 8BA doesn't mean it never happened. The dial is inconsistent with the other known Squadrons, as are the stick hands. This leads me to believe it is likely a movt, dial and hand drop in replacement.
Very likely a Squadron case. As elsewhere noted, this is not a high crime, as at the time watchmakers were simply told to get the customer's watch working again, and another model with the same internal dimensions meant that a swap could be made and the customer on his way sooner. No thought was given to some 50-60 years later and whether the watch would be so closely scrutinized. As watches increase in collectibility, so too does the pursuit of 'originality.'
In reply to The 8BA is from the same by Reverend Rob
Squadron with non-original dial finish. I don't recall seeing this case used for another 50s model. If the caseback fits the case, then the 8BA may be original, as the 8AE is a different shape and would not fit the caseback opening. There should be three Roman numerals etched on the inside of the bezel; those three should match the last three digits of the serial number (515), indicating the back and case are very likely original to each other.
In reply to Squadron with non-original by Andersok