I would be hesitant to go to a re-release screening unless I was certain that the print would be good quality. I went to a screening of the 1997 SE versions of the SW trilogy in 2004 at my college, and the picture was absolutely horrible. I'd hate to think what some of the 1979 prints look like.
It depends. I saw a charity screening of the 1997 Special Edition of Star Wars: A New Hope back in 2004 as part of the grand opening of the new Cine Capri in Scottsdale. The print looked dreadful.
On the other hand, sometime around 2004 or 2005, the Harkins Valley Art Theater started a series of old films that they would play late at night on the weekends for only $3. The 1st 4 films in the series were The Wrath of Khan, The Search for Spock, The Voyage Home, & First Contact. The Wrath of Khan print appeared to be an old one from 1982. It was even missing the "II" from the title. However, it looked to be in pretty good shape, much better than that Star Wars: A New Hope print from 1997.
The Wrath of Khan is much better on the big screen. I'm not sure what it is but all of the model shots look more convincing when they're on a large screen like that.
I wish Harkins had continued that program of old films on the weekend. After the 1st month of Star Trek films, the 2nd month was a bunch of Bruce Lee films plus Brandon Lee's The Crow. After that, they cancelled the program. It's a shame. They'd printed up a schedule for the whole year. November was going to be all 3 Indiana Jones films.

Did they actually have a college screening of all 3 Star Wars films? I was under the impression that George Lucas wouldn't permit theatrical exhibitions of any of the films except for A New Hope.