All 3 of these are cassettes that would have come in the glove compartment of the new cars listed. I think the Olds tape is likely actually from the 1986 Cutlass company car I had at that time but the date inside on the label is 1985.
$10 total gets all 3, plus shipping of course.
1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)