There has been some discussion here. I recall that 1963-1966 front seats are interchangeable in all Darts & Valiants, and probably Barracuda though doubt any came w/ bench seats. I recall people saying that bench seat cars also had the floor holes for bucket seats, but not vice-versa, but not hard to drill holes, though knowing exactly where isn't easy and each needs a reinforcing plate.
Rear seats are a different story since 2 dr need an entry radius (or vice-versa) and of course convertibles and wagons are quite different.