A picture would help. Puppy colors can be misleading. As they get older the colors can deepen or lighten (or both!). How old is the pup?
IIRC all dogs are three colors -- red, black, and white. All the differences are just darker or dilute shades of those colors. So as mentioned grey or blue would just be a dilute black.
Just curious as to whether you'd be upset with a "rare" color or happy with it. In any event it shouldn't affect personality or behavior.