I fired this size Alpine in Grad school.We had several as well. There were refractory pieces for bag walls rather than kiln shelves. No controller.
The kiln looks good but check to see if the controller can translate to propane. I don't know how this controller works or what it controls. It will be tough to move. Make sure (if you decide to get it) to brace the interior well.
The bag walls have always been kiln shelves, but there were refractory pieces that rested on top of them designed to help disperse the flame. They were expensive and time consuming to make, and really didn't make much difference in the performance of the kiln, so I made the decision when I was Alpine manager to stop making them. At that time I also made the call to stop using kiln shelves for bag walls and switched to bricks since sometimes the shelves would warp so badly they would break out the door jambs where they were notched in. I also redesigned the burner system a bit by pulling the burners back from the kiln a couple of inches, getting rid of the cast ceramic burner tips and switching to a metal retention tip.
The controller will work regardless of the type of gas being used. Changing the orifice between natural gas and propane is super simple. The orifice is a piece of 1/4" pipe with three holes in it that goes through the burner pipe. You just unscrew it and put in the new one.
Alpine is now owned by Joe Catanzaro of Kiln-Ray in Warwick, NY. He was one of our best Alpine repair guys back when I worked for Alpine, and should be able to help you with anything you'd need for that kiln.
People rip on the old updraft kilns, but Alpine kilns last forever and fire well. I've seen Alpine kilns that had been in heavy service for 40 years. That one appears to be in really good condition, so you should be able to get many many years or service out of it. They are kind of touchy at first, but once you figure out how to fire it, it will fire consistently and give very good results.