Help needed from exhaust gasket expert!!!

You have the correct gasket.8)

It was made by McCord for Mopar if I recall correctly. Of the hundreds of Mopars I have seen over the last 40 +years,
only 1 ever had the passenger side exhaust gasket.

My Dad bought a 1965 Valiant brand new in October 1964,
at the local dealership Armory Garage, they are still in business, selling Chrysler Jeep and other vehicles.
No more Plymouth though. :(