A good place to go for more info on it would be M715 Zone - Powered by vBulletin
or International Full Size Jeep Association
Either place (forum) will be able to answer any questions you have about it. I can tell you that the M-715 is based on the Jeep Gladiator pickup, was built in the late 60's. It's a 5/4 ton pickup with a 6 cyl hemi type engine, should have a T-90 transmission and a divorced Dana 21 transfer case. It'll have moderately heavy-duty axles, but they'll be hard to get parts for, plus the front will have closed knuckles.
That's pretty much what I know off the top of my head, but either web site can go into much more detail.