I don’t know enough about that particular gun to give any useful direction other than to say that it is a sexy scatter gun. Post pics when you’re finished with it.

Looks better blued.

https://www.rockislandauction.com/detail/82/1508/vietnam-issue-usmc-remington-870-mark-1-wingmaster-shotgun

The originals were Parkerized and had very plain looking furniture without checkering (but had 1.25" swivels for a military sling).
I would do that.

We had them in the Armory on the JFK back in the late 80s and they were parked. I'd say go full ham on it and park it w/correct barrel. I'm pretty sure the ones we used had didn't have the checkering on the for grip though. But that was a long ass time ago so I can't be sure.

Sold my wood stock OHNG for $1k cash last summer.

I believe they actually had a 21" barrel on the original guns, which is hard to find with a rifle sight rear.  There are long rifled barrel that you can cut to size, but normally the rifle sighted smooth bore barrels are 20". Or get a long non-ribbed bird barrel and mount a rear rifle sight to it.  

The 20" barrel is a close enough fix, particularly if you leave it blued vs. parkerized.  But if you want it 'correct', parkerize it and chase the 21" barrel.  Parkerizing isn't that much money, the only problem is finding a matter trigger group as most Wingmasters are shiny.  I believe the trigger guards are aluminum, so you can't parkerize them to match.  You can get the Police trigger guards, which have a matte finish to them.  Maybe a parkerized Duracoat would do.  Decide how deep you want to go and start finding parts.   You can get a Sage stock for it, as there are duty pictures of it shown with the Sage collapsible stock.  Luckily shotguns are out of favor, so other then the bayonet lug or an actual issue gun, the parts are much money.  It's just finding 50 year old parts.

I came across a pair bead sighted version of the bayonet mount years ago.  Mounts only, no shotgun, and bought sight unseen for $60 for the pair.  I knew it was not correct to the USMC version, but the US Air Force did use the beaded version for base security and bird bomb to clear air fields.  Many police departments also used the beaded sight version. When I bought it, the Ohio guns hadn't been released yet (I missed those as I was out at a on-site job meeting).  So it was exceedingly rare when I got it and I was happy to have it.  But even with the Ohio National Guard guns, these bayonet lugs are rare to come across.  I've only seen 1 or 2 others for sale over the past 15 years and I keep an eye out for them.

Mine is not correct clone of the US Air Force gun, but a close enough clone.  Maybe a LE clone if you will.  For the $210 I spent on everything, I'm extremely happy with it.  I have a 20" barrel (cut down non-ribbed bird barrel), Wingmaster receiver and police wood stock set.  The blued finish is so badly worn, that is looks like a parkerized finish and actually matches the bayonet lug mount pretty well.  The Limbsaver recoil pad was nice when I got it, but it is starting to breakdown and is very tacky to the touch.  I keep an eye out for a Sage collapsible stock, but they aren't my favorite to shoot, so I'm only getting one if they are cheap.  I hate the Remington factory folding stock for shooting and am definitely not paying a premium for one, although they do look great.  I do have a Choate side folder, which does lock up nicely, but is less clone correct.  


Rem 870 muzzle end by yellowcarbon, on Flickr

Nice find Sven!

Keep us posted with pics.

To be authentic,  you need to break off or otherwise remove the front sight from the base.

Also, attach the rear sling swivel so that it will unexpectedly fail when at sling arms at 0200 on a rainy night.

That was oddly specific.
Attached File

Nice.

They're correct about the 21" barrel.

Remington later shortened it to 20" (presumably to keep bayonet rings from hitting the front of the barrel during mounting).

Most of the ones shown later in US military service (in pics from the 80s/90s) are missing the front sight but idk why. The base/ramp is usually there, but its dovetail is empty.

The SEALs and USMC Force Recon (pre-MARSOC) would sometimes put the early generation Sage collapsible stock on them.

Looking good!

Yeah they were black. It was 1969 and the Army had already required all the M16A1 bolt carriers to no longer be chrome plated externally because they thought they were “too shiny” and could give away positions.

Looks black, but I don't know what finish was used. The action bar looks darker as well.