D:OS is still gonna get a lot of updates until release, which is on the 30th.... and 11 days is still a lot of days to push out updates, or do you want to download 1gb of updates on release day?
Won't the release version be a different entry in your Steam library anyway, requiring another full download? Iirc that was the case for Dragon Commander (have both the beta and release in my inventory)
It depends on how your bought the game. If you got the early access version, I think they will just make a huge update on release date and that's it.
If you got an alpha/beta key, I think we will have to re-install the game with our new steam key, but I'm not sure if it will be so or they find another way...