"All the knowledge I have about war is about 40 years old..... "
Don't worry sheepdog, that's about how old my own personal knowledge is. My tour in Vietnam was 1967-68, in the Combat Engineers.
Most of the time we had tool kits with us particular to our construction role. As far as personal cutlery I had a Buck Stockman in the top right pocket of my fatigue shirt, and a Buck folding hunter on my web gear. The Buck folding hunter was sold at the PX for something like 12 dollars, and everybody, I mean EVERYBODY, had one. I read in some of these knife magazines where they talk about Randalls and custom knives, but the only high end knife like a Randall I ever saw, was one that a senior NCO had in a rear area. If I had to pick the most ppular knife I saw in the whole time I was there, it was the Buck folder. There were some of the MLK all steel scout knives, the ones called Demo knives, around, but they were not very good knives. They broke a lot of back springs.
Some of the special forces guys had the Buck 119 special or the Gerber double edge job, the MK 1 I think they called it. I always get the MK1 and MK2 confused.
I don't think things have changed much in 40 years, the troops are still loaded down with a ton of 'stuff' they have to hump around. The big combat knives and short sword nonsense is the stuff of knife magazine fantacy to sell a product.
One thing you can ship them, a good compact flashight that takes easy to get AA batteries. Something small and personal for around the barracks at night.