If not, you should be able to avoid re-downloading most of the game by copying or renaming the D:OS install folder before release, and pausing the download after release, moving the files to the new install folder and verifying local files.
One point to keep in mind, should it come down to that, is that Steam now downloads new games to a completely separate directory, and then moves them when finished. So we would need to copy/move it to the "downloading" directory under SteamApps.
