Since it is an 06 production bike, Kawasaki would have to use their exemption to run the bike in the 05 AMA Outdoor competition. And they aren't going to do that with 3 races to go and Bubba out of the championship hunt. So you'll need to wait a few weeks until the outdoors are over. Bubba did turn some laps at Lorettas a few weeks ago on the stocker 06 450.
Bubba and Byrne haven't decided what they are racing for SX yet either - 2-strokes or 4-strokes.... but no doubt they will both be on the 450 for 06 outdoors.... should be interesting