By the way, the length, as you surely have noticed SilverWook, is 1:17:24 (in PAL). So in PAL it's just over 77 minutes. That would make it the shortest version around (unless it was cut at the start due to manual recording), on wikipedia I read:
- Original cut: 86 minutes, released in 1977
- Theatrical cut: 81 minutes
- Director's cut: 88 minutes, released on DVD in 2004
The closest thing is the Theatrical cut then. Maybe the clip from Buck Rogers was removed for TV broadcast so making 81 minutes into 77-78 mins.
I read some descriptions for the novelization (in Italian) and one of those DOES describe THX as an "Adam" of this future social "Eden" (or something along those lines)... I think we might indeed find the origin of this voiceover in the book.