Sorry Wade, but that was a fallacy. Zander only changed the orchestration surrounding the third hammer stroke. The rest of it IS the revised version. I contacted Telarc and made them aware that their sticker proclaiming the recording to have the "original version" of the finale was false. After that, Telarc ceased to put the label on. This can verified by simply following the Dover score with the recording.
There are two or three other strange anomalies to Zander's M6 recording, none of them having to do with a first version. For example, why is there a hammer stroke in the scherzo? . . . I contacted Zander about that, and he denied that it was a hammer. But it certainly wasn't the timbre of a bass drum or timpani. What was it then? I don't own the recording any more, so I can't give the precise location of where I'm talking about.
Differences between the two versions are rather minor in the first three movements, but there are many major differences in orchestration in the finale (no MAJOR/minor pun intended). There's much more percussion in the first version, for example.
In the first version, the 'false victory parade' march music near the end of the finale is very different. Instead of unison horns, Mahler had 3 trombones play the 'parade tune' fortissimo, with timpani doubled by the snare drum (the fate rhythm that lies underneath). One wonders if Mahler might have toyed with having them stand there (I would!). EVERYTHING in the finale leads to that one brief moment, then everything collapses.
By the way, Simone Young nails that very spot (still the revised version).