Are seals available to refurb Boge gland nuts 86- ?

[930yyc]

I'm curious. Does any one know if there is a seal type or number associated with the gland nuts that can be used to track down a replacement?

I have a few that just came off my '86 911 Carrera which held in some shot koni sports.

They are in seemingly servicable shape minus the seal which appears to have been held in place by a spring.

Thought I'd ask before tossing them out,