Let me possibly reinforce that theory. If you look at the serial number of my truck, it is nowhere near what a 1969 should be. Complicating that is the fact that it has no governor or air cleaner on the hood as a 1969 would have. That eventually led to the conclusion that my truck started out as an M724.
I remember when we got brand new M715 trucks in Bremerhaven. I was one of the troops that drove them off of the boat and quickly noticed that something was different. Governor! They were new 1969 trucks. My two previous two trucks were 1967, Ft. Sill and Utah and 1968 Neu Ulm, Germany.
This picture is a 1967 that I had in Blanding, UT. (Truth be known, I still have not decided which way to go with my truck now!)