aaarrrggghhh!!!
Kristy (from the breeder's forum) sent me an email that said if a puppy is parti factore, it's feet will have different colored foot pads. She said that the foot pads usually fill in so you have to notice when they are very young.
Half of my litter with Swany has pink and black foot pads. They are 5 weeks old and still have the pink and white pads. One has small freckles on his lower lip and a couple of "spots" in his chin hair.
So, I am not positive, but I do believe that foot pads are a sign of parti factored pups.