I kind of scored lucky with a purchase of a box of Nam-era M16 parts. It had some cotton olive web slings, 20-rd Colt magazines some with circle 1, and this metal buttstock. From what I can tell it's old and it looks like a Colt aluminum CAR stock, it's been painted in olive but the finish underneath is not the shiny black vinyl, I think it's an uncoated one. No markings on the stock body unless they're painted over but underneath the tab it's marked Newton New Haven. What have I got here, can anybody identify it?

See the pockets/holes in it?
That looks like it's vinyl coated. I haven't ever seen the aluminum stock with pockets like that, only the vinyl top coating.
Nice score.
Check out this thread, it covers the progression of the stocks:
https://www.ar15.com/forums/AR-15/Colt-Retro-Collapsible-Stocks-progression-from-early-to-Newer/123-784452/

Does it fit a mil-spec buffer tube?

Yup its milspec

I thought about stripping the paint but might just leave it as is since I think it looks pretty cool

Is it possible this stock might be Nam era? I got it in a box full of 60's Nam era parts, Adventure line 20-rd mags, OD cotton web slings, M16A1 rifle receiver extension, ect. I know Colt SP1 carbines didn't come out until '78 and I think this is older than that. I don't know if there's any way to know for sure.

Newton New Haven vinyl acetate,  I believe.

There should be markings on the body covered by the latch assy as well as markings on the underside of the latch.

I am far from expert on retro matters though.