Or are you looking for the shorter A1 fixed buttstock? A aimsurplus has the old Colt A1s occasionally, I got one in black. Don't know about OD though.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together. You'll remember the quality of a gun long after you forget how much you paid for it.
US Army 1966-69, VFW Life Member, Retired Geek