I am considering using my Mod.51 as trade stock. May I enlist from the learned S&W experts a possible worth for an, as new, Mod 51 without the box, papers, or tools. Ser.# is M640XX, period grips & bright blue. I am unable to post photos but consider this as an as New Gun, if it has passed other than factory rounds through it the residue has been very skillfully cleaned away. The normal line on the cylinder is almost invisible. Thank you.