Most of the clips are the 97SE - I can tell from little things like the recomposited trench shots, and the little pan on the "I think we took a wrong turn" wide shot. However, it's not the same transfer from the video releases and digital broadcasts. As you pointed out, the Jabba clips from ROTJ have English subtitles on the image. It seems to look closer to how the SEs looked in theaters. Some of the ANH clips don't look like they have the pink shift - can anyone compare to the digital broadcasts?

I'm not sure what the film source of the non-SE clips is. There doesn't seem to be any fading, but I can see dirt, hairs, etc. It's hard to gauge the film quality, because the quality of the video transfer isn't very good. It's very low-res, soft, fuzzy, visible aliasing. They're not from any existing video transfer, but there's stuff like ringing and color bleeding and chroma noise on the crawl, that make the clips resemble an analog video transfer from the 80s. It seems like they cranked out a quick-'n'-dirty 480i telecine for the non-SE clips; it may have even been at 4:3 non-anamorphic and upconverted to 16:9. (The excerpts of dailies and workprints look to me to have similar issues with image quality.)

There are parts where they cut from SE footage to pre-SE and back, like Red Leader's missed shot, where they cut in the original version of the X-wing pulling up from the explosion. We go from this:

To this:

Look at the second image: It seems out of focus, there's jaggies on all of the sparks (compare to the third image), there's haloes on everything.

It looks to my eye like the vertical resolution is even less than the GOUT. On the SW logo pullback, the lines in the logo start "bobbing" and losing definition very quickly.

Perhaps it wasn't deemed necessary to do high-quality transfers just to be shown as clips in a documentary (as I already said, other archival film in the documentary has a similar low-res look).