KettanLadd, I just did a quick search on the courtesy parts web site and I was able to look up the Rear fender. I am pretty sure that they can replace it and I cant see why they would have to cut it out.
Here is the link so you can check it out.
780 Rear Fender & Fitting :: Body(Side & Rear) :: Genuine Nissan Parts :: 370Z Parts (Z34) 2009-2013 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com