I'm not familiar with the article to which you're referring however I'll gladly share what I've seen in these cars (and its sister car the Chevelle).
You want to look at the bottom of the front fenders behind the front wheels. This is a very common area for rust. The rear quarter panels around the rear wheels is another common area. The trunk floor, around the windshield and back glass under the moulding, and the bottom of the doors are more areas to look for rust. If the car has a vinyl top, rust can form there as well causing "bubbles" in the vinyl. You'll also want to know about the floor board panels. Surface rust can be expected here and in the trunk floor but you want to make sure it hasn't started to go all the way through.
It really depends on where the car has spent most of its life. If it's been in the western or southern regions of the US, then the car should still be fairly solid with little to minor rust. If the car has been in the northern region, driven in snow and salt, then it's possible to find major rust. If the car has spent most of it's life parked in a garage regardless of the climate, it's possible the car would not have any or very minor rust problems.
Hopefully this will help and other board members can certainly provide additional information based on their experiences. Good luck with your purchase and we hope to hear more from you about the car!