Phil, I am on the outside looking in but I did buy one of the original brown cowhide FXs back in 2006. I think they tried to come up with any selling point they could to interest people. I believe, without conformation, that all the prototypes you see are designated that way to try to increase perceived value. There is no difference in any of the cameras aside from different color leather. If you are concerned with aesthetics then pick what you like. I like the all black leather without the chrome edges. To me they are the most beautiful Rolleis ever made. But that doesn't change the fact of a Planar lens with HFT coating. The later versions call the lens an Apogon but it is really just the Planar with the multi coatings. I verified that with the company. So the long and short of it is to find a camera with a reputable company that offers a guarantee for some amount of time. It is a great camera and I have had mine for 11 years and it is still like new.
