Yep! However, your Mordred can still be non-binary/trans without the puberty potion, it just affects the sexual dimorphism your character will have (masculine or feminine features)
Edit: I have a trans/non-binary Mordred who's *very* late out of the closet (I'm thinking maybe adulthood if I get the chance?) and I'm pretty sure you still get gender things if you don't take the potions (shooting for a masc Mordred)