I have several spectrum passenger cars, that I quite like. I have the opportunity to buy a large lot of them, at a good price. But they are the older ones that have horn-hooks rather than knuckles. Does anyone know if these older models still have the feature where the couplers swivel with the trucks to assist in better tracking? Also, has anyone got a read on how difficult it would be to swap out the hornhooks for knuckles? I've never messed with the swiveling knuckles on my current spectrum cars, so I'm not even sure how the coupler boxes are set up... Thanks Casey.