If its 73 and later... What you had was a stamped tin and cadmium plated 3/8 thread cutting nut. They didn't have a washer. they were installed hollow side out/up. They would often strip the final thread that they cut in this hollow tube casting for a stud. We would have to pry away the plastic bezel while spinning the nuts to get them off. Sure you could just use a push on fastener but getting that bezel off again in the future would be even more difficult.
