yoda-sama said:

BTW, has anyone checked if that dark spot on the opening Star Destroyer is present on the GOUT?

My guess is that the dark spot anomaly was probably introduced or possibly made more visible when the sequence was recomposited. (except for the starfield, it looks like the original elements were still used) It can also be seen in the '97SE transfers but not in any original sources, if it's not visible in the original due to generation loss caused by the optical compositing or because it's not actually there at all is hard to tell.