What kind of rear sight did it have? The originals were two position "flipper" type battle sights, but there were at least two other adjustable sights used as upgrades. Type 2 milled and Type 3 stamped. All were USGI and can be considered "correct", since they were installed as improvements and are more common than the flippers. Most of those were scrapped, original flippers are scarce. There's repop flippers out there, and I believe aftermarkets of type 2's and 3's.