The main, and only real significant difference between these two earlier versions is that the Laserdisc box set remastered the films in THX (the first time this was ever done on any format).
The two sets are both non-anamorphic widescreen...and so of course are the originals being released on these new DVDs.
The only other difference might be a line of dialogue that may be missing from the Laserdisc set.
The 2004 DVD releases (and of course what's on "Disk 1" of these new DVDs) are anamorphic widescreen.
In 1995, the "Star Wars Trilogy" had its second official release, known as the THX release. The sound AND picture quality were tweaked in these versions.
So if you really want the earliest, roughest versions of the films, the 1992 box set is the way to go.
Yes.
George Lucas released "The Star Wars Trilogy - Special Edition" in 1997. It had further audio and visual enhancements, as well as the additional footage.
These DVDs are not from those...they're form the '93 Laserdiscs.
IMO the SE versions are the definitive versions of the films...just don't ask me why or you'll think I'm insane...
Hope that helps!