You must have missed rocketjocks reply. His 06 has one.
Searching the net, I did find some archived dealer sales specs. The original Suzuki supplied stuff. 04's stated a cat was new for that year, for Calif only models. I wonder now, especially since nobody can find a non-calif stamp on their 07's, no matter what state they live in, whether they did the same thing back in 04, and 05. That is supply ONE version to all states. The change with the welded one piece exhaust makes me think they all might have a cat since 04.