That's what I was getting too....I spent a bunch of time researching this from the big Dometic parts suppliers and the only answer is that the seal is part of the door assembly, and you need to buy a new door if you want a new seal....hard to believe but apparently true.
The seal looks like any other residential fridge seal, so maybe it's a fitz-all part? Kind of like how mfrs don't list every nut and bolt on parts diagrams if they are common hardware store sizes.
Wondering if anyone else had replaced their door seal and if so what part they used. Mine is split the whole length on top of the fridge door.