I may be wrong here (wouldn't be the first time!), but do his front legs look a bit "off" to anyone else? The angle looks quite steep to me...but I am no vet! I know growth spurts do funny things to pups, but I have a friend with a mixed breed that had that angle as a puppy and now she is a big dog with even sharper angles. Again, I am no vet, but it might be something to look into. In the mean time, his weight looks great for a growing boy...and based on his feet and ears, he will be growing a LOT!!!
Dellah - 2yo female GSD/husky? rescue and canine love of my life...
Grimm - male GSD? mix rescue puppy and my first little boy!
+ 3 mares, a siamese/bengal girl, and a rosehair tarantula lady