Looks like an OM that went across the pond as a lend-lease gun during the war. The broad arrow and pennants show British acceptance, and the /380 indicates it was converted from .38 Special to .38-200 by the Brits. I've never seen the large Frankford Arsenal markings on a topstrap before.
The barrel length (4 1/2?) makes it desireable in itself.
A nice find for both the Colt and military collector [img]/forums/images/graemlins/smile.gif[/img]