[ahazra]

He was emaciated when we got him two months ago but has put on about 15-17 pounds since then but hes alittle over 6 months and only about 38-40 pounds is this normal for the breed or does he still look too skinny? He is growing fairly quickly in height, nearly doubled in height.

You will get lots of comments from folks about a puppy that is on the skinny side. I had a skinny GSD puppy too. Bottom line is has your vet checked your puppy for worms, etc ? How is the energy level ? No 2 dogs growth pattern is the same (just like humans I guess). So don't get too bogged down in the details (the devil is in the details). Take a step back and evaluate if your puppy is healthy overall and playful. If that gets a checkmark, then the weight will catch up later.