M-series trailer light receptacle
 

My 1974 M151A2 is upside getting sheet metal work done. My rebuilder is recommended not reinstalling the M-series trailer light socket. Yes, there is one there already, but in his experience over time the harness gets wet and can short, leaving the wiring to ground out and suddenly no tail lights. He has to reroute poorly installed wires for the build.

I have no strong feelings about insisting on 110% show winner authenticity for what is behind the flap cover. Secondly, I have two different small trailers and want to be able to use either. I have a couple pairs of removeable magnetic tail lights which use a 4-wire system if the 1953 MCI-built M100 must be towed. Therefore, I'm looking for a second receptacle to convert to a modern 4-wire trailer wiring circuit. The condition of the pin-set is not important, and the installed piece will come off to be tagged and bagged for the next owner's decision.

Edit - I just realized there is the external flap cover and a concealed female plug. To clarify, I need the female part.