Dealer installed your front plate bracket when you dont need one in your state or provence? Dont freak out. Go check out bumperplugs.com. I remember when I had my Porsche, these guys were talked alot about on the Porsche message boards. I'm pretty sure you could make them fit the 350. I'm sure you can match a colour pretty close to any 350 colour.
Just thought I would ease some of your pain. I dont think it is worth making the dealer order you a new bumper. Better for you to get some compansation and just plug the holes.