Left side of receiver has the "S.G.W" letters in a circle inside a hexagon.  Under that:

"Cal. .223 5.56
Mod.  CAR-AR

A2-U16XXC

(might be "A2-016XXC," or "A2-1116XX0," it's kinda hard to make these out in a pic.)

Lower has A2 features, i.e. beefed up front pivot pin area, thicker rear ring area where stock tube screws in.

Is this a "preban?"  Was it a preban that was sent in to Olympic for "repair," and it came back "refurbished" as it were?

Is such a receiver truly a "preban," worthy of preban price?

Is it ambiguous?

Is it a problem waiting to happen?

Comments appreciated.

Thanks, Ted

Well...

I checked out Oly's webpage and got this:

"Our current production cast receivers have a serial number prefix of "SGW" which stands for our old trade name of "Schuetzen Gun Works". "

I also foudn this:

"U1001 U1597 08/18/1987 11/28/1989"

So....is it possible the A2 and C were added when they remanufactured it?

I would contact Olympic Arms. I'm sure they would have a better idea. THey may not have the original info, but if it was remanufactured im sure they have a record of that.