I found a couple of Remington 870 magazine extension with the bayonet lug and sling mount. I have seen these on the USMC MKII combat shotgun, but they usually have the rifle sights on them. I have heard, but not confirmed, that the later USMC guns had a bead sight on it. I have also seen US Air Force guns with the bead.I prefer the bead over rifle sights, so I was quite happy when I found these. Most of the USMC pictures I have seen have the front rifle sight removed or probably knocked off.
The person I got them from got them in a trade years ago and didn't know the history of them. I am guess it is either a military or police surplus item. Either way, they are in decent shape with just a little wear. Fortunely, most of the wear is on the magazine extension, which can be replaced or refinished.
I picked up a nice plain barreled 870 Wingmaster that I was going to register as a Short Barrel Shotgun. But I may have to do a USMC clone with it. I figure I can chop the barrel to 20" and have it parkerized. Unfortunely, the bolt & shell lifter are both chromed, so I may keep it for a SBS. I may have to search for another Wingmaster to parkerize. Fortunely, they are pretty easy to find in the $200-300 range here in Phoenix.
Does anybody know the standard configuration of the USMC or US Air Force version? I have seen the USMC version with everything from the plain Police style wood set up to older Choate synthetic stocks to Sage retractable stocks. I have a Police style wood fore end, so all I need is a stock. I am assuming the USMC & US Air Force guns are not marked Wingmaster like many if not most of the Police guns (before being marked Police). But it would be nice if it was.