Buying the two pieces you linked from Etrailer is going to give you the same thing you already have - at least that's my conclusion based on your pictures.
This end appears to be a sealed / molded connector. Tt is probably a replacement trailer cord with molded conenctor on it, the same as this:
http://www.etrailer.com/Wiring/Bargman/54-77-003.htmljefffoxsr wrote:
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The other one is a repalcement connectory, because I can see the two pieces: The outer shell and the inner piece which has the screw terminal on the back side, which is the same as this:
http://www.etrailer.com/Wiring/Bargman/54-77-003.htmljefffoxsr wrote:
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