I ordered the assembly from Midway, and it's a DPMS kit.
It was missing the windage screw, the retaining roll pin, and large tension spring that goes under the sight base from inside the upper. I still need one of those.
This is a "Retro-ish" project intended to duplicate one of the highly modified Colt 727's I saw with a certain unit. The one I saw had what looked like one of the Bushmaster-marketed VMATCH rifle-length free-float tubes, with the knurled surface in the middle, with a FSB cut pocket.
It had a reflex suppressor half-concealed under the float tube like an MP5SD, with small Weaver scope rail sections appropriately drilled and tapped into the rail for his Surefire 6P, a PAQ-4C, and a Vertical Fore Grip.
The stock had the slip-over recoil pad zip-tied to it, with the Delta cheek piece.
Lone Star pistol grip
ARMS optic mount, with an Aimpoint
The whole blaster was bow-flaged. One of the coolest Colt Commando variants I've ever seen.
I have everything except the Delta cheek piece, ARMS mount, and Aimpoint. I'm using Cerakote for the simulated bow-flage, since it doesn't wear off like bow-flage, but has the same extreme matte texture when mized to a certain ratio of hardener to ceramic color.