Dash Pad Question for 75 Duster

It’s interesting how Just Dashes requires your pad and I’m not saying it’s right or wrong. From 1970 to 1976 Chrysler pumped out over 2.7 million Dart, Demons, Dart Sports, Valiants, Duster and Scamps. Given all the dash pads were the same, why would they need yours to ensure it fits? That’s like a manufacturer saying ‘we can’t sell you a front fender for your car unless you send us yours first. We need to make sure the new fender is shaped like your old one’. Sure there were production line variances given quality control was barely there but really?