Back in the 70's, I had a '56 2 dr Bel Air hardtop. I used to love pulling in the gas station, telling the attendant how much I wanted and then watching him hunt for the fill. Of course, some of them knew, but most of them didn't. Without fail, first spot they'd look would be behind the license plate. Nope, not there. Finally, when I felt I was amused enough, I'd tell them. Needless to say, I'm quite easily entertained.
Come to think of it, I wonder if anybody has pulled their Tesla, Mustang Mach E or Chevy Volt into their local Sunoco station and asked to "fill 'er up, please" and then cracked up when the guy/girl searched all over for the door.
Nathaniel and I saw a 48 or 49 Cadillac last night. After we looked it over for a bit I said "where's the gas door?" we looked all over. I actually pushed the button on the taillight once and it didn't pop open. But after going over the back end again Nathaniel discovered it and got it to open. I love how clever they were with hiding the gas fillers on the cars from this era.
Behind the taillight, flip the lever and the assembly folds down. Drivers side or passenger side I don’t remember.