1972 Duster...is this a good deal?

Looks like a solid car!

Rust is easy enough to check for, Joe listed all the trouble spots. But I'd be more comfortable with a little rust than a shoddy paint job, and the paint/bodywork is harder to check.

If the bodywork and paint is decent, then its worth the $3500. If the paint and body work is good, its worth that all day long and maybe more, as it will cost you more than $3500 to do a good quality paint job. If it's been slapped full of bondo and painted at Maaco, RUN.

I bought my Challenger with what I thought was a basic, driver quality paint job. I knew it wasn't perfect, but I figured it would hold up OK. 6 years later the entire clear coat has fallen off, and there's bondo cracks, rust bubbles, etc. It also successfully hid some rust in the lower parts of the body. I got a decent deal, so I didn't lose a ton of money on the purchase price, but the car will have to go down to the chassis and bare metal everywhere to be fixed properly.

By comparison, I bought my '74 Duster for $2k. Poorly running /6, but its a '74 so it already had disk brakes etc. All original, no rust at all. Sure, it has a few dents, but I know exactly what I have, and I can paint it without stripping it completely down to the chassis and starting over. And in the meantime, it works great with its new 340/4 speed and 8 3/4, and doesn't look terrible with the original paint.

More info and pictures of my Duster here if you're curious.

http://www.forabodiesonly.com/mopar/showthread.php?t=198098

Like I said, if the paint and bodywork was done well, you'd be way ahead. But if its borderline, you'd be be paying too much for a car that will have to be re-done later. In general, new paint is a red flag for me unless I can track down where the work was done or confirm that its was done properly.