If Bobo Fett were a homozygous dominant (GG), crossing him with a homozygous recessive (gg) would have produced only heterozygous offspring (Gg), making all the puglets black.
On the other hand, if Bobo Fett is heterozygous (Gg), then the crossing with a homozygous recessive (gg) can produce black heterozygous puglets (Gg), and fawn puglets, that are homozygous recessive.
Given that the litter has both colors of puglets, Bobo Fett is heterozygous.
