I've uploaded the pictures to my photobucket site. Double click on the photo to make it larger. Look them over and email me with any questions. Each of these is a stud that's screwed into the plastic dash, then the fine threaded ends put through the holes in the metal of the car and nuts on the backside. I believe there are two that I took two photos of, to give some other views.
http://s90.photobucket.com/albums/k257/2blu442/
I will mention that over the years I've pulled a dozen or more dashes from 1970-72 cars. Most of the time there wasn't a nut on the stud between the AC vent and drivers/pass door, just a piece of flat sheetmetal that the threaded stud pulled out of. But on this dash there was a nut, and when I pried as I did on other cars I broke off the stud. So.... if you can stand on your head with a flashlight and mirror, or if you have extra joints in your arm reach up and feel the stud in this location to see if it has a nut on it or not! Good Luck! John