How to remove Roadster back rest?
 

The leather upholstery on the backrest was replaced 65 years ago, and it’s worn and torn where the driver’s back presses against it.
To be clear, the seat cushion that you sit on came out already. This is just about the back rest. The bottom of the backrest on the passenger-side released from the metal tab with some struggling, but 3 hours of pulling, pushing up, down, or back, using hands, screwdrivers, and even pry bars, along with much colorful descriptions of Henry Ford’s parentage in two languages and still the driver’s side won’t let go.
How is it supposed to come out?
When I push the upholstery out of the way I can see an L-shaped metal bracket up against the bottom wire frame of the seat back. It looks like the seat back should pull up to release. But I can’t get the seat back to rise enough. By the way, the package shelf has plenty of slack so it doesn’t appear to be restricting its movement.
It’s hard to see, but the metal bracket may be bent like a fishhook (not that much, just the tip) towards the rear of the car.
I suppose I could slit the leather to gain access, but I’d rather not!
Thanks for reading this lengthy explanation.

Re: How to remove Roadster back rest?
 

There are three of those L brackets attached to the bottom of the backrest, one on each side and one in the center.