FWIW, I have probably examined a few thousand transferable factory Colt M16/M16A1/M16A2's over the last three decades, and I'd say that on about 60%, the finishes on the uppers and lowers DID NOT match.

Colt made and finished the lowers in batches, put them in bins, and drew them out (not in sequential order) when a contract came in. They also made, finished and assembled uppers and put those in bins. When an order came in, they would look at the configuration spex listed on the contract, and pull parts as needed from the various bins.

Since all factory FA Colts were ONLY built and sold for military/LE/contracts, cosmetics were irrelevant, so most were mismatched in color.

YMMV.

Thank you for the compliment, DaveP1!

Yeah, M16s in general have been an obsession for me since I was a kid (first shot one in the '60s), and in particular, the 9-million serial number range ever since I bought one of those in 1994.

To the OP:

I have a Registry of a couple thousand 9-mil M16s. The earliest SN with the "M16A1" roll mark (the very first ones were roll marked "M16") I have seen is 9103617. To give you an idea of a production date, 91608xx was Form 2'd by Colt in May 1977.

But remember what I said about Colt not producing them in numerical order. For instance, an FOIA request shows a pallet of 72 with SNs of 9268636 through 9268671 (yes, they skipped a lot) was Form 2'd on April 4, 1979.

Yet mine, 9309864, was Form 2'd by Colt on March 7, 1978.

The only way you can find out the exact date of yours is to file a Freedom Of Information Act (FOIA) request, once you are the registered owner. It can take months for ATF to respond, but the process is free, and then you have it in writing. (You also have clues to the original configuration, from BBL and OA lengths.)

About all you can be assured of without an FOIA report is that it was most probably made in the late 1970's.

Hope that is of some help.

DaveP1, that is a cool story! Sounds like your gun has quite a history.

I'm guessing that the serial number on yours is not in the 9-mil range. Colt reserved the 9-mil SN range for LE and Export sales -- AFAIK, none ever made it into U.S. military service.

Of course, all the exported examples could not be reimported without losing their transferable status, so when you see a transferable one today, it is either a current or ex-LE gun, and those did not see the sort of extensive service that mil guns do. Thus, they tend to be in better shape on average.

Well, it never got exported ... some of the LE sales were indeed diverted to private buyers before reaching LE (although Colt threatened, and sometimes acted, to cease supplying any distributors or dealers who did so).

But IMHO, a big chunk of them actually went to LE -- some saw duty, more just sat in racks -- and were then sold off or traded in to SOTs to get newer gear. Plus, the availability starting in the '90s to LE of .gov-surplus M16s for $15 each was a great motivator for departments to trade in their now-much-more-valuable transferables.

The best way to tell, of course, is to file an FOIA. If it ever went to LE, there will be a Form 5 in there ... if it's only Forms 3 and 4, it has always been in civilian hands.