I recently got a Rodenstock APO Radagon 50/2.8 but have some questions about it. The lens appears to have never been use but was in case marked Rodagon 50mm f1:4,0 on it. However, there is a red sticker on it saying, "Neu - mit Vowahlblende New with preset aperture." It's serial number is 1063xxxx. What have I got here? An APO-Radagn that is early production and missing the "N" or something else? I've checked Butzi's site and don't see any APO's with out the 'N.' What is this strange beast?