No. The original "Star Wars" was just "Star Wars" when it was first released, no "Episode IV", no "A New Hope". By the time Lucas wrote "The Empire Strikes Back", he knew that there would be stories before the original "Star Wars", so when it was re-released theatrically in 1979, during the production of "Empire", "Episode IV A New Hope" was added. That's why the "Star Wars" logo goes backwards so quickly compared to the other five films, actually adding additional footage would have messed with the soundtrack, but reducing the time the logo was on-screen gave Lucas the extra couple of seconds needed to add the longer title.
Also, the soundtrack was remixed several times in several different formats and there were little quirks like different/missing lines, but that was more of a mistake than a change that was decided upon.
We all know what happened in 1997, the Special Editions were released with a bunch of new stuff, but the 2004 DVD releases had even more tweaks, like the Palpatine scene in "Empire" re-shot with Ian McDiarmid, the '97 CGI Jabba replaced with a much better looking one in "A New Hope", and Hayden Christensen replacing Sebastian Shaw as the Force Ghost in "Jedi".
So, essentially, you have
1979: Lucas changes the title of the original "Star Wars"
1997: Lucas makes many, many changes
2004: Lucas makes a few more changes
plus the odd audio change every time one of the films was remixed into a new format.
As for the prequel trilogy, both "The Phantom Menace" and "Attack of the Clones" had significant changes made for their DVD releases, and "Revenge of the Sith" had a small one, but it was very minor: one scene transition was a wipe theatrically and it's just a straight cut on the DVD.
No George Lucas-directed film is available on DVD with no changes made. THX 1138 was updated quite a bit in 2004, with CGI and stuff, and "American Graffiti" was re-released in theaters with additional footage and that's the only cut that's ever been available on home video in any format, plus the DVD has the updated CGI title shot, where the plain white sky was replaced by a more visually-impressive sunset.
The Indiana Jones movies all had a bunch of little goofs cleaned up digitally, too. There's nothing of the magnitude of Greedo shooting first, it's just wire and rig removal. Some LucasFilm movies have made it to the format unchanged, however. "More American Graffiti" and "Willow" come to mind.