Yeah, you can have different files/packages sold separately within the same page. There is an issue with it though. It's a bit weird, but considering the SpunkStock Demo was a part of a free bundle at certain points, when a game is claimed via a bundle, you essentially "claim" the whole page's contents, as opposed to specific files/packages. This means that anyone who has claimed this game via a free demo bundle in the past will have access to any files on this page (Even if I uploaded the full version after the fact).
From what I understand, this is how it works at least.