visual indicators doesn't guarantee your animal being het Pied (or anything). as April mentioned, some Normals that are not het have the visual indicators and some don't. some het Pied animals have the indicators and some don't. i just mentioned your boy looking possibly having something else going on visually as compared to your girl who has nothing noteworthy. your best bet would be trusting your breeder and knowing the pairing/genetics that produced your animal.

if u really want to, u could still try to prove him out. u just have to pair him with a female that is a visual Pied or a 100% het Pied for the best odds. even then u might still get Normals that are at least 50% het Pied.