Mike's,
according to this:
http://www.remlr.com/Army-Trials.html
M38A1 was trialed in '58/'59, along with the Landy, Gipsy,CJ-3B (RAF got these), and the Freighter.
This page also has some terrific photo's of the trial vehicles, particulary in the '60's.
Some more info on the trial in question:
http://www.film.queensu.ca/cj3b/Mili...tArmyTest.html
(Although they got the Champ date wrong)
Thanks for pointing me in this direction. Found it very interesting.
Rich.