I have two Norincos. As far as I can tell, they are totally to U.S. GI specs and all parts interchange. There are only two exceptions: the sights are slightly different, and the grip screws/bushings have metric threads.
BTW, I fired one 8000 logged rounds and the other 2000 rounds, with no failures or stoppages of any kind. The Chinese may be "pinko commies" but they made good guns.
Jim