That being the case, and as the barrel, frame, and cylinder SNs match, it's strange that it has a 4" barrel (5" was typical for .38/200 revolvers) and stranger still that there are no "U. S. (or United States) Property" stampings on the top strap, nor any inspector markings. Possibly they were buffed off prior to plating, and the barrel shortened. Can you tell if the chambers have been bored out to accept .38 Special cartridges?