The wrist chains aren't removable, but I bet you can boil n pop, or pull real hard and hope it comes off. Underneath don't match up with the rest of the forearm. It's straight without any vein details. Looks like a stick just connected to the forearm, actually.
...now all I need is the actual Pitt arms, and I can get busy making a villain...
See, I'm wanting to do a Hulk base with clawed hands. think it may work if I take the hands off the arm and try to swap?