Looking at a nickel 58, serial number N237xxx, the serial number is on the butt, back of the cylinder and under the barrel. Also there is a small star prefix on all numbers except the butt serial number. What does the star mean? I thought that when N serial numbers started s&w no longer numbered the other parts? Gun looks all original and is in very high condition, seller is asking $850.00,,,, Soo what ya think?