Here is a video of one of the programs that highlights one of the Chrysler 300 Letter cars:
Here is the episode – Jan. 25, 1961. Skip to 29:00 in the program to see the car: The Price is Right (January 25, 1961 | #61_0016) - YouTube
Here is the episode – Jan. 25, 1961. Skip to 29:00 in the program to see the car: The Price is Right (January 25, 1961 | #61_0016) - YouTube