Muscovy Drakes no not get a tail curl. Both males & females have straight, flat tails... The females will have more pointy tails thoug, the males will have wider-looking tails. The boys also have bigger feet.
So, unless yours are both the same sex, you should be able to tell if you have a boy & girl.
So, unless yours are both the same sex, you should be able to tell if you have a boy & girl.