Brian... Yes, the Commercial Kirbys use the same belt as the other Kirbys. I am told that you should not use the 'knurled' belts on the Sanitronic/500 Series machines, but I always have. As for still being made, no. I believe the commercial Kirbys were only made from the later '60's to the early '80's. The brush rolls are not being made, have not been in a very long time. Too bad, mine needs a new brush roll. It is a cool vacuum, but needs a bigger space to clean then mine.
Justin