Sounds like it could be the rivets in Clutch Plate B.
http://www.partzilla.com/parts/search/Honda/Motorcycle/1998/GL1500C+A/CLUTCH/parts.html#6
Only way to know is to pull the clutch cover and inspect. Not that hard to do. You'll have to look for metal pieces in the bottom of the cover or clutch area.
If it is, the clutch will stop working correctly. When mine went, the clutch worked, just really jerky and the lever was spongie. It was good enough to get home.