Thanks for the links... I guess the black & white one (and colorwise the photo from Steve's framed original) might work to clear out some parts, like the "RON"-lines and the maybe to logo... I'll look into it.
Funnily enough I've already asked Steve about the painting a while back, but it looked like he avoided the subject and never answered about it.
Is the scan from the LA-Archives-manual already filtered (at least it looks like a median filter on it)? If yes, could you upload an unfiltered version? Furthermore, does the manual have an image of MI1 that shows more than the box?
I'll try NeatImage on your 1200dpi scan... although I've learned that it tends to have some problems with screen-patterns at that size.