Ford didnt really change much in interior colors through the 60's and 70's. Most Mustang colors are the same and they sell dash paint for those at any Mustang supply house.
I used a dark Charcoal Metallic Lacquer that I had bought for my 84 Mustang years ago to fix a scratch. Looks good ...
Many years ago at Metro Mustang down by they airport ... Don't think they sell in spray cans anymore though ...
Dave; I just bought some Ford interior black in a spray can. I will get you the part# when I get home. Got it from Melvins, in Conyers.