My understanding of the cat being in the head pipe at the collector is the same as what Supertrapp told you. When I changed my pipes on my '09, nothing was in there as I'm in FL
The left OEM muffler is alot different than the OEM right muffler, which helps make the exhaust system work somewhat like a 2 into 1 with little exhaust flowing through the left muffler and making it more like a sound chamber.