When I heat treat GC rifle boolits, my GC get discolored also, no big deal, the only compromising could be, will they stay on, mine were still crimped/clamped on tight to boolit base. I suspect at that temp, it's more of a heat stain, than actually fully annealed.
So whether you go back to your old ways, or not, don't melt these down. Save them for a test, shooting comparison. My previous post in this thread was made tongue-in-cheek, because I don't think you will see any difference on the target paper at the range. A test would be a good thing...and who knows? maybe I am wrong.
Good Luck.