Ok, that makes sense. I thought it was probably an mkI, but I wasn't sure. The labeling was a big hint too, as it was labeled as a Rank lens, wheras the only mkII I had seen was specifically labeled Cooke. Cooke split off from Rank, I believe, so my intuition told me a Rank would be an older lens.
I'm surprised that you didn't like the mkII sharpness, though. Unfortunately I haven't seen anything (that I'm aware of) shot with this lens, and I live in the middle of nowhere, so I haven't really been able to evaluate it (hence, I've been relying mainly on opinion, which is not my favorite thing to do...). In your opinion, how would you say it stacks up against, say, an Angenieux 25-250 3.7 HP?
Thanks,
Adam