None of the laserdiscs are anything much like the movie was in 1977.

When the D2 tapes were created, the film elements used were run through a telecine, with an operator/colourist whose main job was to get the colours within NTSC legal, and would have balanced the shots by eye on the fly in real time.

So the colour on any of the home versions was whatever decisions the telecine operator made at the time, many years after the original release.

The Technicolor IB prints will not have measurable fade, and certainly won’t have lost any real detail in the highlights vs what was there in 1977. The IB prints were struck the same year as Star Wars was released, so the original elements would not have faded either.

However, if a new print was made for the purpose of the telecine at the time, that print would have had different exposure etc. and may have picked up some detail from the negative that was never in the release prints, such as in the explosions.

It gives some insight onto what may have been on the neg, but not into what was on the prints screened in 1977.