Well old timer, it doesn't look like there were skinpacks available back then. Your only hope is that someone has kept it. Not much chance though as with all the Steam "updates" many have lost old files.
I think, I may have found it in an attachment in one of the old races I did.
Just need to test it tomorrow to make sure it the right one, after I downloaded Race07 etc... from Steam.
If it is I will upload it to the download area.
Hoping to signup for this weeks mini race, once I got everything setup