I'm no expert, but I'd say it's too young to tell. Once they're about 2-2.5 inches it's much easier and reliable. I've seen males have a little dot on their furrow, which my N. coloratovillosus does. Good luck!
I appreciate the input! My son and I got T's at the same time and they could not be more dissimilar. He has a B. albopilosum and I have the vagans. His is a digger, mine's a wanderer. His is shy, mine is outgoing(ish). We thought they were both females, but I'm starting to lean toward male on mine. Either way, we're enjoying having them.
They just look kind of gangly to me. I read somewhere that males tend to have longer, thinner legs, and females tend to have thicker legs. I know the molt is the best way to tell, but so far every thing I've read and heard has contradicted something else. Like I said, I have no idea.