For 70 Cougar I have codes for "dark tobacco".
PPG 23347 is 20% gloss and 23349 is flat. I also show R&M codes for them as well, 170F84, 170F83 but as Jeff said those codes are going to be tough to mix using today's components. Best to find an original color part to use as a sample to have mixed.
If you do find an original sample let me know. I might want to borrow it!
Regards,
Scott