maybe a mix? buff mix possibly, or perhaps a runner mix. I've never seen a duck like this personally, so i am curious what others opinions are.
At 2 months old, you can't tell gender by feathers, but what does he sound like? Is he starting to quack? If it is a loud "duck" quack, then it would be a girl, if it is a raspy, throaty, quiet quack it is a boy.