Originally Posted by DCWilson
Notice the "P" stamp on the left side behind and above the cylinder. That's a government proof mark, and its presence suggests that this might have started out as a British Service Revolver in 1939 or 1940. The big logo on the sideplate along with the single line address points to the late '30s or early wartime years; before 1937 the logo would have been smaller and on the other side. I suspect this gun had a .32-20 barrel and cylinder substituted for the .38 S&W barrel that it would have carried originally......
The P indeed can only mean that the frame was a wartime revolver, however manufactured between later 1943 and 1945. Before then, P proofs were not located there, but on the butt. While ex-BSR's were indeed much more commonly modified, the absence of any British post-war proofs makes it IMHO more likely that this gun started out as a US Victory model. Since the frames were identical and only the barrel and cylinder distinguish the two, probability is all we have, of course.