BuddyPress.org

It should be hopefully replacing the files with the new ones, but you can not be sure , until there is a feature freeze.

As Andy mentions, there may be some unexpected changes(very less expected though) from the current trac to buddypress 1.2 beta.

My advise, if you want, you can go ahead with this, just keep an eye on changes or you may wait till mid of January, then you will have the beta version to work with.