My evidence is the large body of transfers being so consistent. No, I am not intimately familiar with the telecine process. Unless they had some guide they were distributing with the prints, it seem pretty impossible that 13 different telecines done all over the world would end up having the same shots that look different form the Technicolor prints. Add to that Puggo’s work and Team Negative One’s work. And that is just with the original movie. If you add in the SE, you have another set of transfers that are again different.
And except for the English language 16 mm print that Puggo used and the Moth3r bootleg, all the versions (35 mm, Technicolor, pan and scan, and widescreen) have the identical end credits. However, the 3 FX shots (the Falcon being shot at by the Star Destroyer while leaving Tatooine, the composite arrival outside the Rebel Base, and the Rebel fighters streaking across the sky) are not found in any non-English print. The only explanation for what prints they are in is that the earlier version of the shots (in each case the flaw it pretty clear) were from the May 1977 release and the opening and closing credits were changed out to do the home video version. That means this cannot be a print struck from the negative for a telecine. If they need a different print to do the Telecine then it would have to have been struck from the interprositve used in May 1977. These older telecines also have ciggarette burns at the reel changes. By the time the telecines were needed, the negative had been long changed. The first official telecine was in 1982. The negative had to have been changed before the end of 1977 for the international version and probably the wider release later in the summer. So the 3 FX shots archive just when the prints were taken from the O-neg. As you say, it is easy to change the credits.
And all the information about the Definitive Collection LD has indicated the source was a fresh set of interpositive prints. From what I’ve seen of the color of both that version and scans made by this community, the colors are off in a way that is consistent with the orange tint found on an interpositive.
I am not saying that the telecines are identical in all respects, but they follow so close in some ways that differ from the Technicolor prints that I can only conclude the technicolor prints are flawed. If the prints used for telecines are lower contrast than the release prints, then they would have even less color in those Tatooine scenes that look so washed out and it would be even more impossible to pull so much contrast and color out of what we see in the Technicolor prints. No one at Technicolor in 1977 could imagine we would be sitting here analyzing their prints 40 years later. They did one final movie and the prints have known flaws that because of the nature of the prints come down to us now just as they did them. And it isn’t like we don’t have access to the raw scans of other prints to compare to. I have compared all the versions I have and only the Technicolor have those odd washed out Tatooine scenes and the green shadows. It seems like the color timing used to make the master wasn’t quite correct. And I realize that nearly every version I have access to has been tweaked and color corrected to look better, but the sheer volume of transfers and the consistency of what looks different from the Technicolor prints can only point to the Technicolor prints being flawed during the creation process.