RBRacing....haven't checked on them for 3 years or so but back then the parts were "under development".They'll develop them with customer's money it looks like.
If you go on their website there used to be some pretty funny comments from them about some of their customers. Enough to keep me away from them that's for sure.
I just had another tought....did you lift the part number from mainly the spring but the other parts also? Should be stamped on most of them, BMW is good for that. Then punch that into the MaxBMW parts finder to see what it fits. Older machines, never know who could have gone in there and done some hacking/mismatching.
I know for a fact that clutch parts mismatch is a big NO NO for some of the Ks. BMW switched suppliers at some point in the 90s. There are bulletins on that but I don't know if there are any for the R-GSs.
If you feel inclined to dig through that , and there are a lot of bulletins to dig through, I'll send you a link as to where to look. I won't post it here but as a courtesy to a fellow Canadian....no problems.