In my opinion the O-neg has not been altered.
Anyway---at least a 3rd of the so called O-neg of SW was not really "original negative" in the truest sense---- due to the amount of footage that was optically composited.
But for simplicity I will call it O-neg to distinguish it from the original negative pieces that did not make it into this very same O-neg!
The O-neg was disassembled in 1995 so it's differing constituent stocks could be cleaned.
Once that was done Robert Hart re-assembled it.
All of it.
Once it was re-assembled the O-neg was then colour timed using Lucas's technicolor print as a reference.
A new 1st generation IP was then struck directly from this negative.
It was this IP that was then disassembled to remove most(if not all) the shots that involved the optical dissolves/wipes and effects(lightsabers/laserblasts/pilots in cockpits with starfields behind ect ect).
For the original optical shots that involved effects:
The original negative pieces that themselves were NEVER part of the so called o-neg but were used to create optical composites in 1977(that subsequently became part of the O-neg) were scanned at 2k/HD.
They were composited and colour timed in a computer and then scanned back out as negative onto film.
For the other shots that involved wipes but were not effect shots(e.g Vader saying "I must face him alone" and turning his back to the camera---wiping to Obiwan hiding in a corridor)-----the original camera negative pieces were given to pacific titles to generate new optical dupe negatives that were higher in quality than what was possible in 1977.
Meanwhile parts of the new 1st generation IP that exhibited damage because of the poor condition of the O-neg(sprocket tears/scratches ect) that were live shots(e.g a close up of Han's face on the falcon) were also excised and replaced by corresponding shots that were sourced from 35mm theatrical IP's .They were scanned at 2k/HD into computers before being degrained/enhanced .They were then scanned back out to film in negative form.
*These theatrical IP's were culled from various prints found in eastern europe(and were still in good shape having been created a few years before)---this is what Lucas indicated in his interview with Nolan.*
This frankenstein IP(made up of 1st generation live action IP's direct from the OCN + these scanned and restored 35mm IP's) was then converted into an internegative.
The new negatives involving digital composites were also inserted into this master internegative.
The other new dupe negatives(involving new optical wipes/dissolves) were also attached in their designated places in this new master IN.
And voila'.....this internegative was then used to generate theatrical IP's .
The same process was repeated to generate more internegatives and thearical IP's for the January 1997 re- release.
I saw Star Wars in 1977. Many, many, many times. For 3 years it was just Star Wars...period. I saw it in good theaters, cheap theaters and drive-ins with those clunky metal speakers you hang on your window. The screen and sound quality never subtracted from the excitement. I can watch the original cut right now, over 30 years later, on some beat up VHS tape and enjoy it. It's the story that makes this movie. Nothing? else.