If the production line was anything like the current Mini line, all cars are made on the same line and all cars are checked before rolling out of the door on the same line. The badges are placed on by people, people make mistakes. Sometimes the build sheet is put on the wrong car after someone takes it off to check something, sometimes people can pick up the wrong parts (cooper S badge instead of cooper for example), sometimes people are lazy, tired or just genuinely don't notice the wrong parts are fitted, it happens
