I have a strange question - that might be interpreted as blasphemy by some - what would be entailed to color correct the despecialized edition to blend seamlessly into the 2004/2011 releases?
Your best non-manual results would probably be to do a shot-by-shot color match using something like DrDre’s ColorMatch utility. That would cover the overall color changes, but wouldn’t necessarily handle the keyed-out color replacement very well, such as replacing the sleeve colors on cantina aliens. Anything beyond that would involve some sort of manual work. Your lowest-effort results would probably be to buy some magenta-tinted sunglasses.