i was able to remove either the front or rear lens block, but unfortunately i can't recall how that exactly went. however, it should be rather obvious, else i wouldn't have gotten there without recalling now.
(maybe a bit weak argumentation, but that's how my mind works ..)
also, i don't have that lens with me right now, so i can't double check. sorry.
ps: i like the ver. 3 for its slightly longer focus thread.
si tacuisses, philosophus mansisses.