Here's the 1994 Cub Cadet attachment guide. TONS of great info in here if you're trying to figure out which decks fit which tractors and how they all go together. Apologies for it being ~40 mbytes, but it's 50 pages of good info. I've got a higher res scan available too if something isn't legible.
Last few pages talk about mounting newer decks on older tractors and older tillers on newer tractors.
Covers RERs, Lawn Tractors, Series 2000 tractors, GTs and SGTs.