I started working in gas stations in 1961, I've own Dodge and Plymouth B bodies from 1962 to 1965, I 'm almost all of them have the gas cap behind the rear license plate and I would bet money they are all the same part number all 4 years.
I own a 1966 Dodge Coronet Deluxe and it has a gas door in the left rear 1/4 panel between the rear wheel well and rear bumper.
I would bet money that the same vented cap was used on Mopar B and C body from 1962 to 1968 or 1969 or maybe even until 1971