This is really interesting news about the audio, like I posted earlier in the thread, ESB was released in at least five different formats in its original release:

1) 70mm six-track Dolby-encoded magnetic
2) 70mm six-track non-Dolby-encoded magnetic
3) 35mm with optical mono soundtrack
4) 35mm with optical Stereo Variable Area (Dolby) soundtrack
5) 35mm with mag-optical soundtrack (magnetic 4-track + optical mono)

Never heard about or thought they did a dedicated mix in mono like they did for Star Wars, but this proves that at least 16mm prints and perhaps foreign markets got yet another mix. We all thought this would be a fold-down but this is a unique mix, really cool! :)