Roger - There are tips on "buying a used hummer" on
www.humvee.net and also on
www.amghummer.com that are very helpful to someone looking to buy an H1. I did the research it definitely helped me decide what I wanted.
The most sought after H1's are 97.5 & 98 because they have the upgraded transfer case cooling loop, turbo-diesel engine (vs non turbo) upgraded heat & ac, & are before the dreaded TT4 anti-lock system which severely limits the off-road capability of the truck.
Good luck in your search.