[BigMike]

Unspun, also called unrivet, is where the body was not attached at the factory. All bodies have posts that go through the chassis. When they attach them together at the factory they run it through a drill like tool with a special tip that they press down onto the bottom of the posts (like they are drilling it) and the friction heats up the stud as they push it down creating a mushroom head that keeps the body & chassis mated together. An unspun is where that procedure is skipped for whatever reason. Therefore the body just sits on the chassis & you can take them apart anytime you want.