I was looking thru some archived posts and re-read the MVPA article on the M-715 by Doyle.
http://www.m715zone.com/jonmisc/M715ArmyMotors.pdf
On one of the later pages, there is a mention of 43 trucks built in December 1969. These trucks were "slightly improved and intended for comparison tests against the Chevrolet XM-705".
I believe that the truck that member Rocntj found is one of these trucks.
New to this Forum and M715 Ownership
I would think the modified starting button, E-brake, seats, battery box, etc. would qualify it as a slightly improved version.
Another member posted as having an M725 E-1, but I haven't heard anything more about that truck.
Am I on to something here or are the beers catching up to me.
Scott