Haven't installed my bagger yet and probably won't till this fall but I did pull the instructions out and found that they recommend removing that baffle when the bagger is installed. I'm guessing it's used to produce turbulence need and to separate a portion of the clippings that are exiting the chute for better dispersal. I could be all wet though. Maybe someone from Gravely could chime in. PSC also wondered if the mufflers were SS.