I think the mystery is solved -- operator error! The Rolleinars came with 3 pieces bayonetted together. I disconnected the top piece with the black rim and put that on the viewing lens -- not noticing that the bottom piece for the taking lens was really two pieces bayonetted together. I am now assuming that two pieces make up the viewing lens element - the diopter and the prism, I guess, and that the single element goes on the taking lens. If I install this way the dot is aligned correctly to the top. The Rolleinar for the viewing lens sticks out a lot more than the one for the taking lens which basically is a thick as a filter. Does this sound correct?