We've got to clarify something, you surely know but just to be sure. There's 2 CD on that album, first one live and the other a studio one. For having listening to this album many, many times, I cannot believe that the first CD (labeled Live) is some studio work with crowd voices added on.
If your statement is true, it's surely not the studio version of Astronomy Domine on "Pipers at the gates of Dawn" that is playing behind those supposed added crowd voices. And it's the same thing for the other songs on the album ("Set the controls for the heart of the sun" it's not he one from "saucerfull" and "saucerfull of secrets" it's not from the original one too. The song have not same length and it's very not difficult to see that's it's not the same versions.
I think that what you read from the internet is pure lies. It's just for people keep talking!