Change a lens, change the cam, and you still have RF focusing. Linhof introduced interchangeable Rangefinder Cams on the III. Users are expected to mark infinity stops on the focusing track by FILING notches into the track.
This is an important field advantage that all Linhof Technikas/Speed Graphics/Crown Graphics have over monorail cameras.
Not worth discussing here except to say their serial #'s preceded 19,000. In the beginning was the Linhof Technika I and II. Interestingly enough, Linhof actually INVENTED the all metal field camera.