Hey Ash, you seen this thread ?
It drifted off-topic and right up your alley.

JayArgonaut said:

Regarding ROTJ, from what I've seen on my W/S THX 1995 PAL VHS release, during the Death Star battle, just before Han deceives the Imperial forces into opening the rear base doors, Lando says: "Now. C'mon Han old buddy, don't let me down".

According on imdb and here virtually all the other pre-SE home versions have the same line. However, the JPN and 1990 U.S LD contain the full scene (present in all versions from 97' onwards) of Lando adjusting a few controls and commenting: "We're sure in the middle of it now...", after which he then says "C'mon Han old buddy, don't let me down". I don't have access to the 1993 DC or Faces sets to check them (perhaps others who do, can?), but if I'm correct, the JPN and 1990 U.S releases would be the most complete OOT version of ROTJ available.

I recently bought 1478-80, the first domestic ROTJ LD. It's the first pressing by Pioneer in Carson, CA not the later reissue by Mitsubishi.
Here are my recordings of it, both analog and digital, as well as my domestic DC digital only. (DC is the first version, missing the Leia welding bit.)
FLAC are the digital sources; WAV is the analog track.

Equipment chain was LD-V8000 --> M-Audiophile 2496 PCI card.
Like many pro-sumer cards that one has no input level controls, so DC is overdriven to clipping. Belbucus' is the definitive source anyway.

My SC finally arrived from Japan after being lost nearly two months (avoid Celga like plague, Grrr) but I've not unpacked it yet. Might record it later.

I think it's safe to conclude ROTJ was remixed in '93.
Still don't know if the earlier one(s) are theatrical tho