I would agree with Barry that a fender tag that has CAR in place of R1B N1B V1B or what ever engine is a preproduction hand built vehicle or a test vehicle that was built as a test vehicle on the line or off the line to test the assembly process or new parts for the next years production. Likely did not have a drive train assigned to to the chassis till a later date.

These other 1971 Yellow Cudas seem to pop up for sale every year. I use to know of two near were I live. Not sure if they are still around but Ola of the Convertible E Body Registry was keeping some kind of track on this kind of vehicle.