Yes, the seals are available separately. BUT, you must get the right ones and what is in there might not be right. I would assume them to be right if they have been there for years working. In other words; if you have owned the car for a long period and they were working, I would assume what is in there is right.
The ACDelco number we stock is 15-2723 for the thin washer (my Delco book says it is 1.2mm thick. We also stock a 3mm one that is 15-2721).
Bosch Master, ASE Master, L1
33 years MB technician