Over the years there has been 3 basic variations of the camera with several sub-variations.
The Press had a simple RF/'Viewfinder & the 90mm/3.5 lens was standard. It came set up for Mamiya Press backs or Graflock (Mamiya RB70 holders) backs.
The Super had a swing/tilt back set up for either the Mamiya or Graflock backs. Standard was the 100/3.5 collapsable lens, needed to use the back movements.
The Universal had interchangable backs. You could use Mamiya, Graflock, or the Polaroid backs. Standard were the 100/3.5, or the 127/4.7 (Polaroid) lens.
Both the Super and the Universal had bright line viewfinder frames for the 65mm, 100mm, and 150mm lenses (ala Leica M3), the Press used interchangable masks.
My preference was always the Universal, on which I used 6x7, 6x9, and Polaroid backs. The first one had the 100/3.5 lens, the second the 100/2.8. Never had any other lenses. Both were sold do to illnesses --funny, how one thinks paying hospital bills is more important than their camera. I would have replaced them again if life had put one in front of me at a reasonable price when I had the money in my pocket, but it did not. I would say the Universal was my favorite (and most money making) cameras, while I think my Crown Graphic, with flashbulbs, has been the most fun camera.