You are correct with the auger assy, 3 bolts on each end, pull shear pin on impeller, disconnect drive chain, remove the top chain sprocket, ( may need puller), every thing then pulls out the front (auger assy, impeller drive shaft).
Impeller will fall down to bottom of blower (about a half inch), then remove it to straighten/repair as needed.
Rocks are a wonderful thing, I had to replace portions of the blower where the gravel had eaten holes thru the sides and bottom. FUN!!!