I have a M1008 that I purchased from Alfa in October. This situation sounds similar but my issues aren't so dramatic.
The door seals are so-so and the passenger side down right leaks...so much for having been replaced.
The "new rockers" apparently entailed cutting off the old rockers and welding new skins on...when you crawl under the truck you see rusty holes...not a big problem as I was wanting to put some rocker sliders/steps on anyways but annoying none-the-less...
Both doors need new hinges.
The wipers are goofy as they always work but shut off as soon as you shut them off. In other words I have to time it just right so that they are in the down position when I flick them off.
It leaks a little but not bad. About what you'd expect for a 20 year old truck and I'm thinking the injector pump is a bit worn as it smokes quite a bit on start up but doesn't smoke abnormally when warm and going down the road.
My tires also need rebalancing...but then again I doubt most shops know how to balance 36x12.5-16.5 bias plies. I've got some Innovative Balancing beads waiting for the tires.
Honestly, I was in a hurry and didn't take my time looking at the truck with him. It starts up on the first or second try every time (second only when it's cold out...haven't tried in a few weeks though with these below freezing temps), drove me 400 miles home across the UP of Michigan immediately, and is a 50,000 mile 1 ton truck that around here would EASILY fetch more than what I paid for it.
Am I happy with the truck? Yes and no. Yes because it's just about exactly what I always wanted in an old Chevy. I like beef and low options...gimme a radio and a cig lighter, a couple inches of lift of front to keep the tires off the fenders, and I'm about set. Oh, and a 2" hitch.
The issues it has are kind of disappointing because the ads and the sales pitch had me expecting a perfect truck. However here in Michigan what I paid for it wouldn't have gotten me as solid of a truck as I got. It would have gotten me someone's restored vehicle with hidden issues, twice or more mileage, and not as beefy of components. I'm going to fix the issues, build it up a little, take care of it, and enjoy it. Buyer beware.
Besides, now I don't feel bad about messing with it because it isn't pristine.
Do I recommend him? No. I have a friend who has a fondness for old Dodges and he saw those M880's...I basically told him to look elsewhere. If I was to ever look for another CUCV I wouldn't go to Alfa first. If I did it would literally have to be PERFECT and at least up to his description for me to buy it. I'd make sure I had a return plane ticket and demand a ride back to the airport if it wasn't up to snuff...then again I'd look elsewhere first.
I was recently offered a decent shape M1009 for a little below $4000. All I would have had to do was go to NJ and bring it back. The wife wants a cusher ride unfortunately... In some places these are rare and in others people have 5 of them. Ask around.