Certainly not in '64, but the sedans were there in '65, as were the 2% HTs; Tommy Grove had the Missile there, which was one of the latter. There was even a Plymouth ad showing the car there. The 10/15 cars made Beeline. This is from my buddy who ran the Missile after Tommy; talked to him yesterday.
There are videos on Youtube of the Beeline race, I'm told.