Looking at a 70 GMC, help??

[KAILUAZ]

So this 1970 GMC Super Custom 3/4 ton has been for sale for a few months. The truck looks to be in decent condition, frame is straight and is free of major rot. It has disk breaks on all fours and a 350 w/auto trans. Interior is semi stock with seats out of a newer truck. Has A/C, unkown if it works.
I ran the numbers and this guy is the 3rd owner. In 2000 when it was registered it had 80,000 miles on it.
Anyway what should I look for when I call/go check it out? Any areas of special interest on these trucks that would be a deal breaker?
He is asking $2500 firm (from $3500 last month or so).