Most likely you are going to need to have the color matched as best that you can.
I wouldn't be surprised at all if the Pantera colors were sourced from existing Mustang colors at the time.
You can find internet paint shops selling "factory matched original colors" for cars like the Mustang, Corvette, Porsche but having said that, the couple that I have tried are not spot on at all. They seem to be "approximations".
The issue in finding exact original colors is that the formulas are for no longer used paint systems. The colors that I have let my suppliers look for don't even come up in any listings so they don't even know where to start with to get a factory color match.
Even the Mustang colors like Wimbelton White are not right. I'm thinking though that in switching from one system to another, the base tints although being called the same are not so the tints wind up just a little different.
That makes it really tough to do a repair on just one door or fender without color blending it on the spot to match.
What is even worse, if that is possible, in going to touch something up, FROM THE ORIGINAL MIX YOU HAVE LEFT OVER, often doesn't match either.