Have always wondered why some black labs are born with white or pink nails that eventually turn black. They look like bear cubs at birth! And could there be any correlation to the colors they may carry?

Unless the nails stay an off-color, it has nothing to do with genetics and everything to do with the puppy's age. Premie and "early" pups have transparent pinkish nails which go to white and then darken to black.

Those nails have been soaking in liquid since they formed on the fetal pup; once pup is born, the nails can dry out, harden up, and they darken.
Ever notice how your skin is paler and soft when it's waterlogged and wrinkly? and then it darkens as smooths and dries out.......