The fender tag code for Plymouth is TT1 (Med Red Poly) I think Dodge may have called it Ruby red.
The only paint code I have is a couple old single stage Du Pont codes.
1) 4661-LM
2) 181-97417-M
Know body had the code for base/clear except PPG but theirs is a few shades too dark so I took a few parts I had with nice original paint on them computer color matched. It is a 99% spot on match to the original color of the car.