No, the drive on a cadet is different than a Cub, although the transmission appears the same. The Cub Cadet transmission has an input gear, which reverses the drive direction, and changes the input speed to the transmission, to accomodate for not having the final drives like on a Cub. So, the creeper drive on a Cadet bolts to the input gear housing, not directly to the transmission like the torque tube does on a Cub. Also, you would have to modify the torque tube, drive shaft, floor pan, brake linkages, lift rod to the rear lift, and a whole slew of other things on a Cub to accomodate for the creeper drive being inserted into the drive line. You either have to shorten the torque tube (not sure how you would do that since it's cast) or you have to lengthen out a bunch of other things if you don't shorten the torque tube. Regardless, I think it's a whole lot more work than you could imagine.
If you can buy it from the guy, the better application would be to install it into a Cadet!