Also, looking at that 3-way comparison, you say the LPP is in the middle? The middle looks like a different print, it has the 1981 flyover (notice the middle and bottom clips reveal Tatooine out of sync with the music). And just looking at the lasers and explosions, and the milder camera shake when R2 and 3PO are introduced (just the on-set shaking without the optical enhancement), I can tell that the bottom clip is the Special Edition.

I also was not aware that the 1981 composite was framed at a narrower aperture than the 1977. It seems that by the early 80s, ILM was printing all/most of its composite shots to Panavision at that narrower aperture, with the right edge of the frame unexposed. If you watch a print of Return of the Jedi uncropped, almost every effects shot has that black space on the right side.