I just tried going to the CBS web site URL you provided, and couldn't find anything about the Bernstein M2 performance you mention. If you can provide a specific URL to the clip, or to where CBS mentions it specifically, it would be appreciated. I did, however, see the clip at another link elsewhere (I think it was on YouTube, but couldn't find it there after a fruitless search), and it featured the first few minutes of the first movement. What little bit I heard, Bernstein's approach to performance that time sounded about the same as his NYPO Sony Masterworks recording, made less than two months earlier. It would be fascinating if it can be made available on DVD (even if the picture and sound are less than ideal), but I'm certain that there would be various legal hurtles that would need to be cleared before release.
Wade