I recently ran across a RST4 box that is in really great shape. It also has the book, product registration card, and a little safety booklet. I know some of these older boxes are worth a few bucks, so was hoping someone would give me some clues on this one. The serial number written in white down the side of the box is 16-30876 which should put it around 1981. The statement inside the lid of the box is dated January 1978. So anyone want to give me an idea of what this is worth???