As you have probably heard of, the baby with the band aid in the wagon from the episode The Time Traveler's Pig has the band aid in the same place as McGucket. But, the baby was alive 150 years before McGucket. My theory is that they are the same person. The reason McGucket has been alive so long is Gideon! You may be thinking "why would Gideon help him"? Favors. Think about it, why would McGucket build a death-bot for Gideon? He has to. Gideon is keeping him alive somehow, but in return, McGucket has to do whatever Gideon asks. Now, you may be saying "McGucket would have died before Gideon was born". Whatever is keeping McGucket alive is keeping Gideon alive, too. Also, it stops you from aging so Gideon could be 70 years old!
What do you think of my theory? See any flaws or want to add something? Leave it in the responses below!
P.S. I don't mean to be undermining Mf99k's theory, if that's what it seems like.