What you need to use depends a bit on what era M16 you want to dup. Certainly, the first issue used chromed, slab side carriers, but second issue pieces were parked, and once the Army went to the M16A1 all carriers, whether Air Force or Army, were the standard notched type.
Re things like charging handles and flash suppressors, I suppose the very first few AF pieces may have had the first issue pieces, but I've never seen an issue piece, or picture of one, that had them. For my own clone, I've been more than OK with the standard three prong and second issue cocking piece. I do have an original chrome bolt/carrier assy in though
To me, the most important thing in creating an early clone is the lower, and if you want an original looking "short hump/no mag release guard" lower, you're going to have to build your own out of a current piece---which is what I did