I borrowed a Pentacon 6 to EOS adapter from a friend, an inexpensive Chinese product he says, and it fit on this lens like a glove. The wall to the side of the adapter is thin enough that it misses the protruding pin by a mm at most and makes it work. I think the particular adapter was designed with this pin in mind. Whew!!
While I don't think this zebra lens is the Olympia version (they were silvery metallic, AFAIK, and would be great to have), these zebra versions are well respected, and even with a single coating it renders good color and contrast. I have seen many of these zebra variety without the pin, including another one of mine. Yes, I did get a little greedy and ended up with two :-P