[RJay]

Well, that barrel marking was used 1899 until 1911, The D Prefix was used twice in that serial number range, in 1901 and in 1911, Since Iver Johnson didn't go to a strengthen frame until 1909, I don't know if you have a smokeless frame or a black powder frame. Maybe I'm missing something, don't know. perhaps a picture of the bottom of the grip with the patent dates would help. That file mark does not look like a"memory notch ", but rather like a cut mark a small child would make with a three corner file. Memory marks or coup marks were made on the grips. FWIW, the ideal of gunfighters notching their guns is more or less a dime novel myth. Wasn't done as a rule. More notches were carved after the 1900's than ever before because of the dime novels and the first cowboy movies. There were laws, Coroner inquests and hanging ropes even in the old " lawless days". Even the assassin Jim Miller didn't notch his guns, why advertise that you killed someone. There may have been one or two to do so, but I've never read of them. BTW, many a notch was cut on the grips in the present era to add spice to a gun story and to help sell the gun and story together