I found this bit about early changes on this Wookieepedia page.

The earliest edits to the original film occurred between the initial release in May and the wider release later in 1977. The edits are minor, but noticeable. They consist of four changes. All of these changes were made before the foreign language prints were made later in 1977 and well before the last good interpositive was struck in 1985. These four shots run exactly the same length. All of them exist in the earliest bootleg video tapes and in the English 16 mm print. The original three effects shots exist in many home video English language versions released during the 80’s. None of these shots are found in the Definitive Edition, Faces Edition, or 2006 bonus discs, nor are they in any of the known extant 35 mm prints, or Technicolor prints.

When the Millennium Falcon is being chased after taking off from Mos Eisley, the effects shot where the Star Destroyer is shooting at the Falcon was changed. The early version has different explosions and different flashes and looks less finished.

When the heroes arrive on Yavin 4, the outdoor composited shot with the matte painting of the temple is recomposited and is not synced the same. It also has an artifact in the image.

When the fighters take off from Yavin 4, there is an extra cloud and the shot is not synced the same. It also has an artifact in the image.

The scrolling end credits are completely redone with the spacing, both vertical and horizontal, altered and a glitch in composition at the beginning has been removed.

This is the first I’m hearing of this. The article mentions that these only exist in the earliest bootleg tapes and the English 16mm print. Does Puggo Grande contain the early version shots? If not, where can I obtain this version of the film?