Hey Fellas, I can't make any worthwhile comments on this piece since Im still functioning at the pre-school level in ID'ing originals, but let me remind us of something we might not realize! From Colonial times up through today, there is and has been a brisk trade in North American hardwood timber going to Europe. It is entirely possible, I would think, that a piece could be made in a European country and be stocked with American Black Walnut. Or Maple. Or Elm, Black Cherry, etc.
Many German WWI rifles were stocked in American Black Walnut, as were the earlier WWII German 98k's! American hardwoods were dirt cheap by European standards from the Colonial Period foward to the start of WWII. I'm just thinkin' that maybe we ought not to forget this when we try to narrow down a country of origion based on wood identification of the stock