I highly doubt its gonna be a day one patch. They are hardly gonna release to patches in a day. If they release one, it will be quick fix to bugs people encounter in the first day, or maybe 2-3 days if there arent any major issues that make the game unplayable (for some). So it will probably come in a week, or whenever they release a patch fixing all the issues of the first days.
Might be wrong and they might release it just at the same time they release the game, and then keep on with hotfixes as usual. But I doubt it. I think the patch will come with those first hotfix patches.