Not a great answer, but an answer nonetheless.
It's implied that the monks of The Order, in the 68th Century, restored his body.
> > and for that matter I don't remember the issue were he actually lost the arm to begin with.
It was at the end of the Messiah Complex crossover (X-Men #207?), his arm was bitten off and eaten by the original version of Predator-X. He stole a robot arm that Forge had built, lost an eye shortly afterwards, in the Cable series that followed Messiah Complex, so that he could look like "an evil version of Cable". Well, an evil-er version of Cable, I guess, since we already had Stryfe, who he'd later team up with.
I don't even remember how he lost the eye, though. Anyone know?