I think that last rim makes the difference. Some don´t sand / file that rim down, and so they can't focus to infinity (or only with live view).
I have modified my Rokkor 58/1.2 and it works well and up to infinity. Documentation here
I have converted a Rokkor 35/1.8 to Canon EF, but that conversion was quick and dirty - had much time becasue of my small daughter. German documentation
With that lens infinity setting on the 5D is very narrow - probably it only works because of imperfect parallelity.
