Assembly line errors aren't out of the question.
A guy I know had a '72 Matador sedan. There is supposed to be a "Matador" emblem on each C pillar. One side was correct, the other side had "SST".
I saw a story on another forum from a former employee at an AMC dealership. A customer took an Ambassador for a test drive and complained that it pulled hard to one side while braking. Back to the dealership, up on the lift, front wheels off... drum on one side, disc on the other.
Or maybe your car is a prototype.