They were most likely a dealer add-on. My dad put mud flaps on the Challenger after he bought it. They were smaller flaps that had a chrome strip on the bottom. They accually looked good...unlilke most mud flaps.
A few times, I've seen where people attach mud flaps with those black springy clamps you hold papers together with. You can easily take them off at shows and put them back on before you leave. I even saw someone that made mud flaps out of clear plexiglass and held them on with those spring clamps.
