Saddle back....Blanket back....Bi Color...what's the difference?
I just searched "blanket back" and there are lots of threads with puppy pics and then adult pics. The one above shows some blanket backs, and the pups look similar to yours, maybe? So maybe he could be a blanket? Lol, I don't know. It's so hard to look at a GSD pup and predict what they'll be. There is so much variance even within the different coat types. Blanketback/saddleback/bicolor/sable/black sable/red sable/light sable/black and silver lol. And THEN there are people that claim something is a bicolor that others say is def isn't a bi but rather a black and tan. The same with black sable vs dark sable. Is there any other breed with that type of craziness within it for color?!
The best thing to do is look at the parents. Do you know what his parents looked like?