The version Gareth Edwards saw was likely the current Disney+ version since it was in the works at the time.
Almost certainly since he mentioned at the time they just completed a new 4K restoration.
I remember him mentioning/referring that it was the actual original version. Maybe my mind is playing tricks on me. If he didn’t then yes, it certainly would be the D+ version.
I remember this to. He said it had the original effects and everything. He watched it around filming Rouge One.
And around the same time a box was found in the falcon room. With many unused/ used footage.