Several people have asked questions about A2 handguards, especially the ones supplied by PSA.  So, I took out some I have to show some of the differences between them.  There have been other good threads on this topic before. (I have included a link to one at the bottom of this post)  I don't know enough to give dates on when each appeared.  Maybe someone else can help with that information.  This is just observations from handguards I have personally handled.  Please add your own observations, or ask questions of these.

So, here goes.
From Left-to-Right in all photos: New GI replacement "shiney", Late A2 "matte finish", PSA tapered oval, Cavalry Mfg. C-5 Fat Rifle Handguard

Top view
All have the same number of holes.


Inside view
Neither of the A2s is marked "Do Not Remove".  Note the straight curve heat shields in the PSA and Cav MFG.


Side view
The two A2s are round tapered. The PSA is oval tapered. The Cav Mfg. is oval and straight-sided.
All have the same number of ribs, but the two oval handguards don't have a wide band at the very front.


End cap view
All are molded for triangle end caps.
The top half of the C-5 is cut away for a piston gas system (one heat shield is also deleted).


Delta Ring view



Also, look at this thread for another comparison of A2 and PSA.
A2 USGI vs A4 round handguards

very cool info, thanks for the share.

I'm a fan of the GI shiney these days.

The A2 handguards from Windham Weaponry will fit the bill for you then. Mine look just like the shiny replacement GI handguards in the OP.

C-5 is chonkay.

The C-5 handguards make the PSA handguards that are on my 6.8PSC A4 upper look skinny and the PSA ones look fat next to my Windham handguards.

Ok, from both my personal experience while in service and a little light collecting. In 1987 I was issued what was essentially a LNIB M16A2 when I arrived at my first duty station. I don't remember the entire serial, but all the M16A2s I carried over the next 4 years and 2 duty stations (USMC) were in the 61 or 62 mil range. All the furniture was similar in texture as what you find on A1 furniture, smooth and what could most correctly be called semi gloss. Not shiny, not flat just a faint buffed look to it. The PG had a slight grippy texture and got a little shiny after usage. The heat shield did not have "do not remove" (hereafter "DNR") on the inside. I got out in 1991 and stayed out until 1996 when I join the NG. Oddly enough the unit I joined had M16A2s and they were used. I do not recollect any being restamped M16A1s but I didn't really pay attention to any but my own, and it was a Colt and the furniture was similar to what I used my 4 years in the Marines, except now the hand guard heat shields had "DNR" stamped in them. We all removed them for cleaning anyway. In 2001 I got issued a LNIB FN and the stock was the same as before, not the ashen gray looking stock, and the PG was more glossy than usual and the HGs were dead flat with "DNR".

Now on to what I've collected.
I have what seems to be unissued early A2 HGs, complete with the early shields. The area exposed under the HG holes is a strip dyed greenish gray.
I have a single shiny HG and the shield is stamped "DNR" in skinny text and there is no dyed strip where exposed.
I have a single HG that has a sand blasted texture that is smooth on the raised ribs. The shield has a fat text "DNR" and the dyed strip looks sprayed and almost has a 2 toned appearance.
I have a set of what I call FN HGs, they are take offs and dead flat, fat text "DNR" and sprayed dark gray strip.
I have a set of late A2 HGs, dead flat, skinny text "DNR", almost black dyed strip and the shields are glued in.

I have decided not to get into the commercial HG sets I own.