Zeiss 180mm Questions

I am considering adding a 180/2.8 Zeiss lens to my Yashica/Contax collection. There seem to be two different versions. There is one, I think the older one, which narrows at the rear and another which does not. I am not concerned about AE vs. MM or G vs. J. Is one version better than the other?

I had the later one that doesn't have the taper, it was a MM, I think a J. I sold it pretty quickly as it was soft wide open and there's not much point having a f/2.8 lens if you can't use it wide open. I replaced it with the Tele-Tessar 200/4. As far as I know, the optical design is the same in both versions. The coatings on the later ones may be improved as Zeiss claimed they were continually improving them.