I really hope someone can answer this question. No one seems to have answered it so far. I haven't put too much time into it yet for fear of this but I know some of you are like 30 hours in. Since they say the patch is being approved for certification can they confirm it won't require starting over?
Most of the patches for New Vegas and Fallout 3 required a new game for the effects to kick in.
i.e., having a broken quest and downloading the patch won't fix the quest. You have to start over so the quest won't break again.
Although sometimes the patch actually does work on the old file. Performance issues in general were fixed in the same file. Usually things pertaining to NPCs required a do-over.