Just a very nice Colt Commando, and likely sold out of service to "NPD" following its war-time or DSC issue. But whatever it did for the war effort and subsequent police service, it couldn't have been carried often. Finish is at 95-plus%.
A similar one sold at Poulin's Auction in May, 2017. It had the NPD NO 21 marking on the butt. It was speculated that it was for the Newark Police (Newport, Napa, who knows?). Seemed a little pricey at $1,000. But maybe a bidder or two knew something more than the average Commando collector
Mine is right in the middle of the 50,000 unit Commando production run of 1942-1943, at serial number 23,001. It was made while the Flaming Bomb proof was still being applied, though lightly struck. The NPD NO 17 was definitely applied post-production, as the address clearly cuts through the parkerized finish.
Full series of pics in the following post. Enjoy, and thanks for looking.