The songs do blend fairly well together, with a few minor adjustments, but I don't think its the demo for Given Up, mainly because LPU albums tend to clarify if the tracks are demos to a released song (Ex. Oh No, Sad, Fear, Drawing, Bang Three, Pretty Birdy; all those tracks and pretty much every other song states in their titles that they are demos to songs from their studio albums) I've also heard Grecian was maybe a demo for Given Up, but as far as I know, they dropped the song and didn't expand further on it from what was heard in the Making of MTM.
Now that I think about it, I'd be very interested in hearing a demo for And One. This song appeared on the HT EP and several of the Hybrid Theory Demo CD's before the final version of the album released. I would really like to know if there are rough seeds, alternate vocal takes, or different-sounding instrumentals on early versions. I find it strange that the exact same version of the song was released each time while other songs, such as Carousel and Part of Me, had at least two different versions available.
The live version of And One they played was different from the original version that appeared on the EP and demo CD's. I'd love to hear a studio version of that one.