Welcome and there ia a ton of info here on this site. In short, the military went through several iterations of head gaskets until they found one, and torque specs, that they felt holds up better than the previous ones.
The multifuel engines are all high compression engines and that is hard on the head gaskets. Fact is, if you DO own a Deuce, chances are that it had head gaskets replaced in the past or will need them in the future.
Do not fret about it.
Try and read up on what is normal when it comes to oil seepage and leakage around the head gaskets, how to identify the head gasket style ("old" style has weeping tabs sticking out) and compare that to what you see on the truck you are looking at.
If the prospective truck has signs of head gasket failure, negotiate it into the price. If it has a new style gasket, you know they have been done at some point. Many trucks here still have the "old" gaskets and are doing just fine.
And lastly, if you need to do head gaskets, all the info and guidance on how to and what to is right here.
Have fun and good luck!