It's actually somewhat harder, but only by the reasoning that you need to change the floor tunnel out.
You'd need the crossmember and isolator system from an early truck (1989-1991), but the later system will work in the earlier truck, too.
Pre-1992 Getrag 5 speed is it's own crossmember, but 1992/1993 was a mix of the old and the new and used the automatic crossmember and isolator.
I outlined some of the differences in a posting over on DTR a while back:
http://www.dieseltruckresource.com/dev/ ... r+isolatorMark.