Like @derobert explained earlier, durations of 1st movement differ dramatically. According to Tchaikovsky-research 1st movement of revised version is 368 bars long when original version is having 486 bars. Revised versions are usually around 10-12 minutes when original is closer to 16 minutes (if you follow tempo markings by the composer). Recording of 1st movement by Karabits (2011) has a duration of 12:25 and recording by Gergiev (2011) is 11:58 long. Both also mention "Allegro vivo" section on their title instead of "Allegro comodo" which would be tempo marking for the original version. I'm familiar with both of these recordings and can confirm these to be standard versions.
Both of the releases having these recordings mention rarity of the original version on liner notes:
Gergiev (LSO Live LSO0710): "...he made a thorough revision of the symphony, in virtually re-composing the main body of the first movement, and it is this revised version that is almost always played today."
Karabits (Onyx ONYX 4074): "Seven years later Tchaikovsky substantially revised this symphony, rewriting most of the opening movement and making minor amendments to the other three. The original version was actually preferred by Kashkin and by the composer Sergei Taneyev, but it is very rarely played today."