Go check with the GS guys on here, on some years the fill quantity was changed so may not correspond with your rider's manual. May not apply to you but worth checking on. I think you have a drain plug on yours unlike some later models and that can make oil changes trickier.....not having a proper drain plug.
You should also do the wheel shakes, just in case the big bearing is going.Easier to find that way than crunching on the road. I shake that wheel everyday on the road. K-bike but same rear drive and same potential problems.
I also change mine often, just in case I see weird stuff on the magnet, that's also a sign of problems. Cheap prevention, that's only a cup of oil or so and a few minutes work. A gallon of Castrol GL5 80w90 goes a long way.
If ,and only if, you notice a problem, don't ride it like that. Can escalate real quick as in a few miles and can make a repair much costlier.