Just bought my first Rickenbacker after wanting one since I started playing and I'm absolutely in love with it. Got a great deal on a 1990 red 330, after doing a bit of research I found its a BT model. From my understanding this stands for "Black Trim" since the pick guard and all the metal is black. Are there any other differences between a BT and non-BT model? It looks like the BT's were made from the mid 80's to the late 90's were BT's a small subsect of the guitars made during this time or was everything black trimmed?

Also Ive never owned a semi-hollow guitar do I need to put a humidifier in the case during the winter? I live in MN so it gets pretty cold and dry.

Thanks!