I think this may be a 1953 Douglas. The 8BC 21jewelled movement is marked L3. The case is 10K White gold filled and Marked Bulova with the serial number 8070840. The dial is a grey with raised silver numerals and hour markers the hand are silver. I bought it for a snip as it wasn't working. This turned out to be a bent pallet bridge. its working fine now.
It's a fair question. Other examples we seem to be able to line up both the movement and case dates. We have an example of L0 stamped on the case yet the serial number begins with a 3, but this may have been a 1950s thing (https://mybulova.com/watches/1948-douglas-4793)
Generally speaking though, most examples look like their movement and case dates line up, so the subject watch might have a donar movement (might).
That said as there is no other model it could be, then we would ID as a Douglas, noting a possible replacement movement, if we date the case to 1948, which is perfectly inline for this model.