Your post has my head spinning. You've got about 20 minutes of conversation and rolled up in it.
I think $3K for the listing you shared is probably high. He states that he drove it for "at least an hour". So what? He had to get it home somehow. He hasn't offered any guarantee or told you what he has done to make it worth paying more than GL auction price for the truck.
He says to check his feedback. OK, check it. He doesn't have any feedback for an MV.
As you've said, keep your eyes open. Also, at this point, I advise you keep you wallet closed. Find a few MV owners near you. Link up and soak up some info.
For what that truck is listed for you could enlist the aid of a SS member or two and buy a truck with a lot of loot still in your wallet.
M44 series deuces can be up to, what?, 57 years old? I don't think there's any such thing as a deuce you can buy and drive to "show off" without an expectation of having to be prepared for putting a fair amount of work and, maybe, money into it. They are medium duty tactical 6x6 vehicles with all the strengths and weaknessess that implies. They were designed at a time when labor was cheap and manhours were plentiful.
There was never any expectaion or intent that they would be trouble free or that they would run a long time between breakdowns.
Please understand, none of this is intended to discourage you. I'd be pretty low on the list of folks who wanted to do that.
I'm glad you are looking for info BEFORE buying. Fortunately, you are in a part of the country that is close to a lot of places where deuces are coming out of GL. I'd advise going to look at a buch of them and asking, through a thread, for inspection help.
Good luck and I hope you find a good truck.
Lance