Got it!!!!
I am now the proud owner of my own M715.
The Serno is 15816, delivered on 09/1967.
Currently has 29412 miles on the clock.
Pics will follow as time permits, but for now the description. It is mostly complete, but the wiring has been hacked up quite a bit. The body is pretty rough, but rust free. Tailgate will require a good bit of work, but I'm motivated about salvaging it. Rest of the body will require a lot of hammer and dolly work.
It was purchased from the GSA sometime in 2004, and has been in private ownership since then. Prior to that, it was being abused by the US Forest Service.
Doug