While the engraving could have been done anywhere, it looks like Japanese work, not German. There is no way of knowing, but like Jim Watson and Waidmann, I think it is occupation era work, sometimes called "carton of cigarettes" engraving because that is what it cost Americans.
Mostly I have seen it on war souvenir and personal weapons but in this case an American may well have "liberated" his issue weapon or one he acquired. If I owned that gun I would be in a quandary whether to put on stocks that would complement the engraving or leave it as is for its historical value.
Jim