Since the definition of the word mutt is unknown linage, then yes, he would be a human mutt. And honestly? There are a lot of humans out there who do not know where they came from. As for the dog, IF YOU KNOW FOR A FACT that the dog is a German Shepherd and Lab mix, then yes, the dog is just a mix. But if you are just saying that due to coat colors, then it is a Mutt. Make sense? Of course this is how I see it. :P I meant to put above that mixes don't always mean mutts.