IMHO, it is definitely NOT a PCR, of which no examples are known in the US.

It LOOKS like a "school gun", but I think it is a wannabe. Nearly all SGs are on 1899 receivers. They ALL had carbine sights. Most of them do not have the normal cartouche. Stock should have a band-retainer pin - I don't see it. Bayonet lug is not beveled. The whole front of the stock looks quite "fresh" and recently "disturbed". The filler block on mine is nearly invisible, and heavily oiled/patinated.