01 is a bastard year, combination of 16 bit and 32 bit electronics, I can't remember off the top of my head what's what, but I know most things don't interchange. 99-00, 01, 02-07 are the interchange years.
Suzuki did some odd things like that. My Gen 1 Bandit was a 2000, this was the same year the Gen 2 came out so I had to be real careful ordering anything to ensure it was the Gen 1...
I had a 2004 Heritage Ford truck, the same year the new body 2004 came out, same thing, I had to be real careful making sure I ordered for a heritage model...
I'd imagine the same would be happening now with Ram trucks as they sell the older body style alongside the new bodystyle...