The backside mounting bracket is what will be hard to find seeing as you have to reuse it when you replace the plug with a fog light. You may want to check
850 Rear Bumper :: Body(Side & Rear) :: Genuine Nissan Parts :: 370Z Parts (Z34) 2009-2010 :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com. I'm thinking it's part 85242 for $22.