I have a 3 and a 5 window. The three has no rust anywhere and the 5 has a rotted floorboard. Is it easy to remove the 5 window top and switch it with the 3 windows bottom of cab to make a new rust free 5 window cab? Should I just repair the entire floorboard on the rotted 5 window cab? Another catch is the 5 window cab needs to go on the 3 window's chassis.