I checked quickly and it looked like HD footage from the blu-ray to me. I didn’t take a close look but the shots that I saw of original footage looked pretty shitty to me, definitely not HD.
That unaltered shot of the Falcon and the last remaining fighters flying away from the Death Star right before it blows up and the unaltered Death Star explosion are still there. I don’t remember if the SE shots earlier in the doc are replacing unaltered shots or if those were already SE.