Just for fun, and I'm no expert, but I would say he is from American pet lines (which I think there is nothing wrong with!) This is my reasoning:
His head/face: It looks very typically American to me, maybe that is just my opinion, but I haven't seen that head shape in the male German show or working lines. In my limited experience I have seen more 'roman' nosed dogs in American lines than in others, although I am aware they are not specific to American dogs.
As far as coats, I think there is a broad spectrum in all lines. My female is predominately German show line, but her coat is fairly short. My West German working line is much more plush than she is, and most of the working lines I see are close coated... so I think there is a lot of variance in coat between the lines.
He does not appear to be very angulated, that is why I don't think he was American show lines, although he is not really stacked in the pictures. I guess anything is possible really, and he really could be German or American or a mix of both. If not American, my guess would be American and German working... just a guess.
Either way, he is a handsome dog with a really nice dark saddle