Thanks for the replies!
The buffer tube lock ring is not staked. I also noticed the ejection port door spring is in backward, and the cut on the door itself is kinda crooked. Also the pistol grip is not colt, has that cheap feel of the ones that come with the LPK's. The pistol grip screw is hex head, and the flash hider has a crush washer behind it.
So it's a fixer-upper. I have a set of Colt six hole handguards, a Colt A2 grip, and a peel washer I can add. I guess I'll try my hand a cutting another ejection port door (I think I can do a nicer job than this one). But the things I'm still unsure about:
Charging handle, mag button, and delta ring; these should be gray right?
Buffer tube: two position, also gray?
I'm thinking about a NoDak Spud buffer tube and charging handle. Normally I would just spray these parts for my clone rifles, but I'd like this one to be really nice.