if memory serves me right the nylon coated aluminum two position stock is only unique to the original Colt R6001.
The slab side lower receiver was standard issue on all or 99.9 percent of pre 1989 manufactured Colt AR15 series carbines and rifles.
The two position 2nd generation nylon stock became the new issue on SPII series carbines, the four position stock was a new concept and issued to the tactical carbine AR15A3 years later.
The magazine fence did not become part of the AR15/SPORTER Blue label until just after Colt reissued the line back to the general public during the late 1990-91 time frame.
Please correct me if i am i error but, the only colts i have owned and used with mag fence are of blue lable origin. As one example have very early blue lable Colt 6450 9mm carbine that was issued two pos stock, bayonet lug, the mag fence and retains that silly sear block.
The receiver is marked AR-15 9mm carbine with the name Colt in the upper portion of the lower receiver. The funny is that the Pony within the circle is not die stamped in the lower which is real weird.
One could only guess what the mind set of colt was during this time period. I know during this time some early pre ban blue lable guns were released from the factory with pre 89 parts and specs due to parts on hand and retained all or most of the "evil features." some guns issued with the old AR or SPORTER die markings with the K prefix to push a more realistic or Public relations shit with a fancy 22lr convertion was just a bunch of fancy PR bullshit. It made me laugh more than twice, Anyway have a good goo one.