Never saw rear pads be identical to the fronts...EVER. Reason, rear pads are intentionally smaller, as is the disc because you just don't need that much stopping power in the back (controlled stops typically are 70% Front 30% Rear)...so the demands are so much less...! Personally if the OEM maker (in this case HD) does not use the same formula for front and rear and basically put all their R&D experience on the line with safety compliance boards looking over their shoulder, do you think an aftermarket company "knows better" and is REALLY willing to stick their neck out and use the same part numbers?...don't think so, and would NEVER use the same pads for the front on the rears...unless the OEM ones are used and they have it in writing!