Here's my original operating manual for the player and on the cover, it shows both. Wonder if one was for Fairlanes or other models since the bezel is shaped a tad differently?
Cheers
Dave
The lower one in your image is the under dash mounted dealer installed variety optional player.
Only Mustangs, T-Birds, Cougars & Lincolns received the factory installed versions (in 1966 & 1967 anyways, do not think anything changed in '68).
68 had changed to an available AM/FM Stereo option and added the push-buttons for the Mustang 8-track player but I am unaware of any 68's with FACTORY INSTALLED 8-track players WITHOUT the buttons.
I imagine some very early ones could have been sold without the push-buttons, perhaps using leftover inventory from 67 cars (wasn't that popular of an option yet). I am curious to hear if any unrestored 68's with a matching Marti report has ever surfaced WITHOUT the push-buttons.