I find this very fascinating, also makes you wonder how the audio mixes were treated, I have always thought of this first cut as The 70mm version instead of just an early cut of the film.
If this was the case, it must mean that a total of four audio tracks were produced for Empire albeit all of them very similar in content, a 70mm six-track and a regular Dolby Stereo for the few 35mm prints that were made of the original release cut, and the same procedure for the "Final cut".