I'm playing with mine here now. I really like the frame counter on the Rolleicord I. The film is advanced to (1) in the red window, and then the mechanical counter is set to 1 by pushing the little button next to the counter down. The counter doesn't stop automatically when you wind the film, which can be an advantage to the Rolleicord II, as there are fewer moving parts that can be affected by dried old grease.
It has a 3,8 Triotar instead of a 3,5 because the shutter used at the time didn't allow larger apertures.
I used a bright fresnel viewing screen in it for a while, the original Rollei screen for the GX/FX which fits but is a little bit thicker. I easity adjusted the focus by removing the leatherette and screws on the front, and just tilted the front so I could loosen the set screw for the viewing lens. Then I adjusted the infinity focus on the screen and tightened the set screw. Voilà! Later I put the original ground glass back, and did the same procedure. I don't mind the darker screen.
