"EPISODE IV - A NEW HOPE" first appeared on the rerelease print of STAR WARS that came out AFTER the release of THE EMPIRE STRIKES BACK.
Other than that, the films have remained the same, no scenes were added or deleted until the 1997 Special Editions.
There are unsubstantiated rumors of people that saw the Biggs Tatooine scenes in the original film print, but they may have just saw a workprint. No hard evidence to corroborate that.