For that 72, condition and originality is probably going to be the main drivers of price. The condition looks decent, but you really can't tell from the pictures. You'd need shots of the trouble areas (cowl, trunk, floor pans, rockers, frame rails, etc). For originality you need to find out if the car is numbers matching, has a fender tag, and build sheet. If it has all those you can start looking at the other items which are commonly replaced (radio, battery, etc).
For that price I would expect it to be numbers matching, have a fender tag and build sheet, have better than driver quality paint/chrome, and be virtually rust free. I would start knocking off $ for the items I found lacking.
Assuming it's numbers matching, has a fender tag or build sheet, has the typical rust, less than show paint/chrome, and has had some stuff replaced, I would offer more in the 15-20 range.