Might be an OSS or General Officer's Pistol version also. Don't know who to contact, but you might be able to get hold of an archivist at Rock Island Armory (GOP program administrator) and see if the c/n matches any ever issued to a general.
Aspen and Midas, very nice weapons to both of you! Moonclip, I'm looking for a couple beater Model M's myself as long as they're mechanically viable (ideal would be still safe to shoot, but a 0% finish--I'm thinking to Parkerize as GOP-replicas, since I'm a WWII junkie) and affordable. Wher've you been seeing 'em, if I may ask? All the ones I've seen in WA are too good of finish, too expensive or both.