Even in the modern era, you run into issues with 1/2 model years when new models come out. I had a 2000 Chevrolet 2500 that was a half year, or a late 2000 vehicle. I grooved up the rear rotors while playing in some sandy mud. I went to the dealer to get GM replacement rotors. They looked the same, but the original rotors were an 1/8" shorter on the hat. When the new rotors were installed, everything was good until the wheel was torqued down. The new rotors contacted the dust shield. It took a call to corporate to figure out the issue, and a couple of weeks for the right and proper rotors to be delivered.