Does Rise of the Samurai change existing vanilla save games?

I've been enjoying my Rise of the Samurai campaign thoroughly, but I've also been keeping in the back of my mind the Chosokabe long campaign that I was in the middle of before ROtS was released. Does anyone know if the new battle maps and other changes reportedly affecting the original campaign will take effect in games that were previously saved? Also, if anyone has a list of what changes to the original campaign have been made with Rise of the Samurai, that would be great.