I was looking at a 1976 Rolls Royce SS II recently. It has the factory 8-track in the burled wood dash

I presume that we're talking US Spec. European/UK models at that time had a Blaupunkt radio with shortwave and a completely separate underdash cassette player, which didn't even sport a rewind button.
Options included a cassette recorder, which also gave you a rewind button and a mic., although I wired it up so that I could flick a switch and leave it recording the end of radio programmes after I left the car - useful!
You could also get a footswitch fitted to operate the autotune.
I still have the whole kit and wired it up just recently to answer a question in another thread.
8 tracks never really cut it this side of the pond, but I did have a friend who had a recording 8 track in his house. Fine except for the track change every 10 mins., the 80 min tapes lasted just a few uses.