Wrong cars are often, counterintuitively, highly regarded because of the questions they raise. how Did this pass quality control? Where was it built? Did someone have a bad Thursday morning? This happened often when cars were largely manufactured by humans but is extremely rare in the world of strictly regulated automated production. So a 2024 Ford Mustang with mismatched seats is a real rarity.
How this could happen, I’m not sure. Parts are closely tracked from assembly at the supplier, through shipment, to which production vehicle the part is assigned, and when it is due to be installed. Those of us who are interested in new things often see barcodes on all kinds of parts. This is how they are indexed and tracked for production. Not to mention the stringent quality control that modern cars are subject to, with a dedicated force of inspectors ensuring the car is built to specifications.