Based on that pic of the GS in the sand, you cooked the clutch.
If in doubt, replace the part, replace any marginal seals back there while they've got the bike split in half. Its much easier and cheaper to do it now. I would be very doubtful of reusing any part of that clutch. Who knows how it warped? I looks like you're missing about a quarter of the friction material.
Yes clean & lube the splines of course, but also remember / learn how to treat a dry clutch. Roasting the clutch assembly probably only exasperated the spline lube issue. That orange dust in the pics may be the metallic remnants of the spline lube, not rust.