I recall reading about the GS when researching the R65 before I bought mine. (Perhaps it's on Noemi Berry's site; I can't remember.) Anyway, the source said that the R65GS was manufactured and sold in Europe for several years, but never exported to the USA market. I note that by the currency in the eBay listing that both bikes are for sale overseas, so the listings are consistent with the previous information.
I haven't seen any information re whether any GS bikes have reached the States via "unofficial" channels.