[VAC] Standard Airstream Trailer Hitch Connector???????

[FWSLOART@xxxxxxx]

Greeetings,
I am looking for a 60's to early 70's Airstream 17 to 23 feet.
In the Boy Scout tradition I want to be prepared.  Is there a universal 
trailer plug to truck wiring set up?
Diameter, Round or flat pins (contacts), Number of pins, configuration??????
My person that is putting on our hitch says we should know what kind of 
connector to have......
Any suggestions?

John Semon
john@sloart.com