124630/WF-23 a Douglas EF-10B Skynight in VMF(N)-531 markings

The 'N' in the squadron number denotes 'Night'. In those days there had to be different aircraft for different jobs. As Jo rightly points out, this one is really an electronic jammer version. The only reason I can suggest for its being painted in this scheme is that the paint gives better protection against the elements.

Done