I have a Model 1905 revolver SN C 4191xx. Appears to be a three screw right side plate. 38 special. No model number on crane or frame. Checkered or knurled front sight with a slight ramp. 4" bbl. Square butt. Magna grips with checkering. Finish shows original blue with numerous areas of blue wear apparently from holster. Most interesting thing about this particular gun is that the back strap is marked "THP 253". I live in Tn. and this may be an early issue Tn Highway Patrol piece. Anybody help with this manufacture date? And anyone familiar with how THP identified their early guns. My guess is that the stamp was an armory number. It would have made inventory very simple if revolvers were hanging on dowels in the barrel.