The YS-1 and YR-1 codes for "custom" seats doesn't mean that they were specially ordered with different seat cover material from the cloth that was normally used. They mean that the car came with Deluxe interior, which many 79's came with.
Your seats are not from a 79 with Deluxe interior, or the seats were recovered at some point with the wrong material, since no 79's came with that seat material. Those seats could very likely be from an 81, since 81's had that kind of striped material, called Pimlico.
Also, having custom door panels just means that they were the Deluxe door panels, and not that they were ordered in a different color. If the door panels were black, someone changed them.
On your body tag (cowl tag) on the firewall, there's an interior code which tells what style(standard or deluxe), color(obviously red), and material(cloth or vinyl) that the seats were. So, that's what you would go by to restore your interior. It's apparent the color is red, and that it is a Deluxe interior. The pull handle on the dash shows it's a Deluxe interior. All we need to determine is whether the seat material was deluxe cloth(hobnail lombardy) or Doeskin vinyl. If you put your cowl tag codes here, someone can translate them.