Mopar part numbers on the plug 3498227 72649 B-804

For an oval hole roughly 2.25" x 1.25"

My local Mopar dealer said they only have access to searching numbers back to 83 and this was used in the years 61-81

Anyone know what this fits? I searched the 72649 and a similar plug popped up for a newer Ram but its thicker and definitely not this plug.