Hey Carl,
Well, your R/T was built at the LA plant (all T/As were built at Hamtramck) , and your R/T was built several months before the T/As hit production. So, I would have to guess that the antenna was moved at some point? Was there any evidence that either the passenger side fender or quarter panel or both had been replaced? Is the car coded for a radio or is it radio delete?
T/Ake care,
Barry