No, they are not Carter.
They are Funder Wheels Go Kart which was run by the same guy who founded Action Performance who launched some of the first Nascar Die Cast collectibles.
See article here;
Action Performance Companies, Inc.: Information from Answers.com
I had one of these small go karts and they actually have a plastic chassis. it is strong for plastic, but very small wheel base and more a toy than an actual go kart.
Anytime you see the sterring wheel like the one shown in the OP's listing pics, it is a Fundercart.
HTH
Keith