This “special look” wasn’t made to go out to theaters anyway, and probably can’t be streamed on youtube in anything higher than 1080 (although please correct me if I’m wrong), so the OT footage coming from a higher res source wouldn’t have made any noticeable difference, hence why they went with the off-the-shelf blu-rays.

It’s worth noting that the first teaser trailer for RotS back in late ‘04 used the then only recently finished Lowry master for its two or three ANH shots and in fact used the alternate camera angle (the close-up of Alec Guinness) for Obi-Wan’s “for over a thousand generations” line. In the actual movie we don’t cut to his close-up until the “before the dark times” part IIRC. I don’t know if that alternate angle was also the OCN or if they used another source, but presumably LFL had it restored just for that teaser.

Similarly, the first trailer for Crystal Skull used footage from the Indy trilogy. I don’t know if it was from the ‘03 Lowry masters or the 2008 remasters (the ones that were broadcast on WoWoW and which were used, with a different color grade, for the eventual blu-rays of Temple and Crusade).

It would be cool if they did something similar for the final trailer in October. The teaser trailer from April went out to theaters as an actual 4k file, so if they were going to use OT footage I feel like they’d want it to look as good as possible.