Newbee with some questions

[Rusty one]

Getting ready to buy a 63 C-10 short bed.First time owner of these trucks.. Not sure why these trucks are named different (fleetside,stepside). It already has been lowered front & rear and it has a disc brake 6 lug set up with new brake lines & hoses. My question is...I noticed some rot under one of the doors,I know no one makes replacement doors (except the skin) Id like to swap the door for a good used one....Is 63 the only year that will fit,or will other years fit too?..