It all depends on the developer, big games like this usually always have a preload, sometimes it can be a week before launch, but usually it's at least 3 or so days before in my experience. You also have to manually preload the game, it won't do it automatically.

When you preload a game it will still have to unpack at the time of release which is a lot slower on a regular Hard drive than on an SSD. For people with very fast internet it can be faster to download the game at release than to preload, but that all depends on how fast the persons internet is and how big the game is.