Removed from my 2001 F650 GS when one year old to go with an Ohlins upgrade, at about 2,000 miles. In dry storage ever since, no rust or corrosion from a Ca. bike, made by Showa with remote pre-load adjuster. Said to fit '01 to '07 GS not low versions, maybe others, part number 33537728374, with a Mr. BMW list of $994. Eye to eye is 12.5", spring diameter is 3.25", and uses 10mm bolts on each end.
If the ad is up, it's available, so inquiries asking "if available" and or without a phone number will be ignored. I don't text, and have limited time for emails so they won't get answered without a contact number. So, a phone call is best for a prompt and accurate response. John at 53ZERO-477-71FIVE8