1972 Dodge Dart 318 Swinger. Is this a fair price for paint and body work?

$4 to $5k is not at all out of line for a decent paint job. It might be a GREAT price depending on what you're getting. Show quality paint jobs often start at $10k and go up.

Biggest thing that I would recommend is looking at the shops previous jobs and talking to former customers. It's not hard to make brand new paint look good, the real test of the shop is if it still looks good in a few years. Go look at other cars they've painted, talk to their customers. Any decent shop should be able to put you in touch with a few happy customers.

For example, the paint on my Challenger looked pretty good when I bought it. 4 years later the clear coat has almost entirely peeled of, and the color isn't far behind.