This parts kit is currently being auctioned on Gunbroker. https://www.gunbroker.com/item/844989788
USAF issue colt 604 upper manufactured 1969-1972 (see C MP C barrel marking). This upper has not been refinished and is in excellent condition for a 50-year-old GI rifle. The bore is flawless. The 604 with its lack of forward assist is one of the more distinctive M16 rifles, and this is a prime example. There is a small crack in the handguard plastic (see photo).
Included is: the appropriate (and uncommon) type D stock. The period appropriate (and uncommon) colt manufacture bayonet. A museum style display stand with period appropriate GI M16 vehicle mount. And finally, an appropriate gray finish partial fence retro lower receiver from brownells is included. Must ship to an FFL.
Nothing else is included, allowing you, the collector, to save or splurge on this project as you see fit. For as low as $350 you can finish this project with Vietnam era parts, if you shop around. Or maybe you already have the parts.
The display stand is solidly built and has 4 coats of indoor/ outdoor primer. The paint job isn’t perfect, but it would be nothing to sand the imperfections and give it a final top coat.
Since this will ship as a parts kit and lower receiver the purchaser can have their FFL put the receiver in the book as a pistol. This is the trendy thing to do now days since you can use a pistol receiver in pistol or rifle configuration.