After going through a collection of audio I have from the haunted mansion, I noticed that there is a change in audio for the stretching room. Originally, Paul Frees did three recordings of the narration for the attraction for Disney to choose from (the first hardly resembles the narration we've come to know), but the second and third versions were the almost the same narration, with slightly different tones and added words, just for variation I guess. (For instance one difference I remember off the top of my head was "...make room for everyone. There's no turning back now" was changed to one sentence: "...everyone
because there's no turning back now".)
I noticed that the entire stretching room audio had been changed. Originally the spiel went, "Our tour begins here in this gallery where you see paintings of some of our guests...". The narration was changed to "...our tour begins here in this gallery. HERE where you see paintings..." It's the only thing that really makes the change noticeable, although it's a completely different recording than the original, and when compared they do sound a bit different. It might also be worth noting that in this new recording the pauses bewteen the ghost host's lines are longer, so I'm assuming the whole stretching room sequence has been extended if only by a few seconds.
Just one of those tidbits of useless Disney information.
edit - unless it's been this way all along and I'm comparing the WDW and DL stretching room audio. If so, the DL version is the narration most commonly heard online and on cds because the other one is different from any master narration I've heard (and I really don't take the time to analyze the audio like this while I'm in the parks

.)