I saw a Detective Special at an estate sale. It was incredibly dirty, but I took a chance and bought it. When I cleaned it up, I discovered it was in incredibly good condition: no fore-aft play in the cylinder, good lock-up and timing, and no corrosion. The forcing cone and bore are perfect. There are a couple of scratches in the blueing, but nothing major. With a serial number of 5799RD, can anyone tell me then year of manufacture? Thanks in advance.