Just bought our first Magnum. After getting it home we noticed there was a cd stuck in the player (the dealer failed to mention this.. ). Would actually like to change it out for a 6 cd changer. Questions is, if we buy a used/refurb radio, will the steering wheel controls plug in and work? The radios we are looking at say they will work for our year/model. Also is there any way to get the model number of the old radio without taking it out?? Thanks for any help!