I was preparing to convert my B&O Smooth Sided Passenger units to A.Wells couplers, but I'm not able to determine how to best remove the existing coupler. I am suspect that it needs to start with the gold rivot as seen in the attached photo. Could that rivot have a hex slot or do my eyes deceive me? Following that I see another small screw under the magnetic decoupler hinge that will most likely release the entire coupler. Does anyone have any experience with these particular MTH passenger trucks? They do not match other MTH passenger trucks that I have (they are a mixture of metal and plastic ). Any advice would be greatly appreciated.