I was told that a 4-speed tranny will not bolt up to an engine that was designated to accept a 5-speed box, and vice versa. Different bolt pattern and slightly different primary case and cover.
The 5 speeds came online in 2004. I have a spare '04 engine that I am rebuilding for a custom project and was looking for a 4 speed box for it, (I like the looks), but the importer says it wouldn't work. I am sure there is a way to do this, (adapter plate, some machine work, etc.), but its been my experience that after you fiddle-fart with something long enough, and spend enough money onit, you end up just wishing you had bought the correct item to start with.
Good luck to you, but if you want to sell that 5-speed, I'll be looking here in a few months.
SteveJay