As pointed out earlier, what the states call things is pretty random, and not necessary for us the owners to follow.
The states put all kinds of crazy stuff onto titles, due to either mistakes made by the issuing office, or due to local state registration / limitations of available wording when checking boxes on forms / etc.
Over on a British classic car forum people get confused all of the time by strange things that were on their title, incorrect year of manufacture for instance, and don't realize its just a mistake and doesn't mean all that much other than making them order the wrong parts if they don't do their homework about what they actually own.
