Am looking at an M&P 1905 .38 Special in NRA VG condition for possible purchase. It's serial number is 4693XX. It appears to fall into the broad range of M&Ps made between 1920 and 1925. The dealer swears it hasn't been re-blued; it has a little holster wear on sharp edges and end of the muzzle. The grips are nice and have the "diamond" around the screw but there is no "S&W" Medallion on the upper end of the wood grip. Does anyone have an idea when the grips starting having the medallion? Any idea of what the worth of such a revolver is? The Bluebook values vary a lot from what old police guns bring on the street; so, I would appreciate input from collectors out there.