Can a labrador's nose still turn black if it is still pink at 2 weeks?

Have you checked the reputation of this breeder? I'm no expert in the subject, but I do believe a pink nose is an undesirable trait in Labradors, and no good breeder would breed a dog that has one. The goal of a good breed is to better the breed; which means not breeding dogs with undesirable traits. If you want a lab as a pet, I'd recommend going to a local shelter, they probably have a ton. Also, I read somewhere that pink nose labs tend to be aggressive and their puppies are even worse.