Hello..I inherited a 1970 (or so) Fender Scorpio that was equipted from the factory with two wonderful JBL D120F speakers. The amp's tone is definitely not my cup of tea. I removed the speakers and was surprised to see that they have copper colored dust caps. Kind of odd I think. They definitely have never been removed from the cabinet since day one. I'm curious what their value is ? Grey frames with yellow tab on the magnet cover. They're in excellent shape. Any help will be appreciated.