Here is the information we have been using for the 4-5-6 Chevy truck interiors:
Med. Fawn 60% gloss DuPont 9171-L, Ditzler DL-22571, Rinshed-Mason 65B84
Dark Fawn Zero Gloss Du Pont 9202-L, Ditz. DIA 22568
Light Fawn? 60% Du Pont 9170-L Ditz. DL22569
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Medium Saddle 60% Du Pont 4626-L Ditz. DL-22570 Rinshed-Mason 65B83
Dark Saddle Zero Gloss Du Pont 9199-L Ditz. DIA-13010
The Saddles are from '65, all Fawns are same '65 and '66.