Tim, I can't tell whether the louvers came out easier forward, or out the back -- and I've never bothered to unscrew them to find out. But they have to come out one way or the other.
BUT, if they come out best via the back side of the fender well then getting to them will be more difficult, but not if you also opt for the extra venting. You can see on my shot below that if you have to remove them from behind taking out the vent will give you ample room by working through the vent hole.
