Those look like the original cotton canvas seat covers sold by Ford for the car. I've had a set on almost since new. They fit a little loose, and I had cutouts put in for racing harnesses. When new, they had to be soaked overnight in salt water to set the black color. They have functioned extremely well, still look like new, and stop the rain from getting the leather wet when you open the door during rainstorms. I have not seen these anywhere for many years and they are probably unobtanium now. They were, I think, made by CoverCraft.