Want to confirm the purity of breed

Question
Hi,
I have adopted a german shephard puppy of age 4months. Its ear were up since last 2 months but im preety confused about the purity of breed of this dog. Its black and off white, not completly tan at the bottom. I want to ask do the pure german shephard puppies used to change there color in few months or will he remain same like that.
Another question is that, is it important for all german shephards to be slanting from the back. My dog dont seems to have slanting back,its almost straight from shoulder to tail. I got its pic,will send you if u want for further clerification.... Thanx, Take care

Answer
German Shepherd puppies are born solid black, and develop other colors continuing until they are full grown.  Some of them never have any brown or tan.  they may be known as silvers.  I think the slanting back is prized in show dogs, but other lines bred for working dogs tend to have straighter backs.  So none of what you have told me suggests your puppy isn't a purebred.  You might check the shepherd pages at www.akc.org.  They are heavy on breed standards and show dogs.  Not all purebreds meet their breed standard.  I once had a purebred Lab that had a white tip on his tail like a beagle.  I would have been laughed out of a show with him, but he graduated as a dog guide and was given a very demanding assignment.