Do a google search for RockShox RS1, there's several sources for seal kits available out there.
The main seals are just orings and could likely be matched up at the hardware store.
I just resealed one on a buddies Nishiki, every oring I needed came from a generic oring kit.
The wiper or dust seals were good enough to reuse, especially since he doesn't really use off road.
Personally I'm not a fan of shock forks, they're heavy, offer little benefit due to the limited travel, and
when they fail in a way they can't be fixed, it can be hard to find a suitable replacement after so many years.
By the look of the bike, at least judging by the pics, the bike doesn't look to have been used very hard over the years and the seals are likely just dry rotted from age and not damaged from use or worn out so a simple oring replacement may be all it needs.
RockShox Seal Kit