So the frames I got from eBay don’t actually work for my lenses, and here’s why:
They are beveled for glass lenses. Mine are plastic.
Who knew? They are the exact frame style (RayBan Predator), the exact model number (RB 4010 PS16 642), the right color, etc. etc. I did not know to ask whether the lenses were glass or plastic. Oh well!
Perhaps it is time for something new! From eBay?