Just to add fuel to the fire, when I saw the film theatrically about 3 years ago it was presented 4:3 open matte - this would appear to be the format of the release prints as well as the original negative.
Of course, few mainstream theatres these days are equipped to show 4:3, and I imagine it was much the same situation in the mid 80s - perhaps Reggio and Fricke simple allowed for the inevitable masking when creating the original compositions?
Which makes it kind of hard to reach a definitive answer as to which is the proper version (unless anyone can quote Reggio on this point) - however, if the IRE version contains more picture information, and has a sharper image, that kind of makes it a no-brainer for me
