Ok, I see now... your original post link goes to a two prong high current plug. but your thumbnail in post 8 shows the 7 pin plug.. got it now.. tnx.
That's it, James.
The same style (form factor) of the plug and receptacle is used for many different pole (conductor) configurations. On this page there are listed at least 1, 2 and 7 pole connectors that I believe all have the same "housing".
Trailer Connectors, Coiled Electrical Cords, and Heavy Duty Plugs and Sockets
Chris