Hey man.....
The pipe is the RS... the 1st generation, now they have the RS2...good pipe too...
It APPEARS to me that, yes the case is a L.C. S9 that was converted to A.C....Pretty easy to convert AND a LOT cheaper to repair/build/fix VS. the L.C.
NO, the A.c. NEVER had rear disc..... nor the ppl model
Either the top end was converted to A.C.... OR the rear axle was swapped out for the L.C. axle (it is longer) to accommodate the swing arm and brakes.. THIS would be the easiest way unless you had the parts and a broken engine.