Are they on the front OR back of his legs??? Many labs tracing back to some well-known English lines have so called Thumb prints on the back of their feet. While these spots are technically a disqualification according to the breed standards, MANY purebred labs have them and they do not mean the dog is not purebred.
I have also had purebred, champion sired out of champion mothers who had white spots on thier toes and chests and one even had a white tip on his tail. While still purebred, this is obviously NOT desired and is a disqualification for showing. These mismarks were neutered and sold as loving pets.

Toto, CD, RN, CGC answered on 4/25/11. Helpful? / 1