Looking at a 1980 c3500

[srfinatsunset]

Hey Guys
I have been a looker on the website for a while now finally took the jump.

I am looking at a 1980 C35 Sierra Classic Camper Speical 3+3 dually. I have seen a few pictures of the truck inside and out. Nothing to close up. I have talked to the owner a few times about the truck. 454 automatic California truck. I don't have the vin yet to see what those details tell me. I know A/c doesn't work. Owner said it needs to be recharged. Unsure of mileage due to gauage cluster being changed out. The truck was lowered and has Alcoa rims. Air bags in the rear. The truck was a daily driver a few ago now is just weekend fun truck. Owner did driver it to Havasu last year said it ran well. This truck will also be my weekend boat puller and fun truck.

What other questions should I ask the owner?
What should I look for on the truck?

I have been trying to find information about these style truck but have seen the same few website a dozen times.