I haven't researched part #s yet but I'm guessing bumper cover is unique to RS6, the deck lid not.

Yesterday mine fell victim to cell phone idiocy.

I got off easy. The event ended up with one guy - the perpetrator - hitting a tree bigger around than a basketball at abt. 50 mph no braking whatsoever, only some sm amt of speed scrubbed off by smacking & grazing across my bumper. Ugly.