Yes, they molt, but yours may still be dead. A molt will be empty and will often fall apart. An entire crab with the innards intact, means your crab is dead.
I haven't seem mine molt but Im not saying they dont. I got one and hes a beast, I bet hes the size of a 50 cent piece right now. I lost a fish some time ago and I think he ate it all him self. The others I put in the same time are all about 1/2 or less his size. But again I have not seen any signs of their molting. My banded shrimp just molted for the first time and my fire shrimp molts every other week it seems.