If you look in this thread:-
http://www.originaltrilogy.com/forum/messageview.cfm?catid=2&threadid=801&STARTPAGE=1
on the 1st post of the 1st page scroll down and look for thse two releases...
Star Wars: The Original Trilogy - The TR47 Version (Letterbox)
Star Wars: The Original Trilogy - The Anamorphic Widescreen Version
there may be enough info for you to decide which version you want.
Hope it helps.