Evidently, the practice of marking guns with identifying information has been around for a while. Several years ago, I bought a Model 1816 Springfield .69 caliber smoothbore musket at an antique shop in Gettysburg that was converted from a flintlock to a percussion cap ignition in the 1840s or 1850s. The lock plate has Springfield and 1838 stamped on it but the customary eagle was ground off indicating it was possibly a Confederate musket during the Civil War.
Under sunlight, I could see printing scratched on the shoulder stock: John McGess 1868. I found a McGess family in West Virginia, but no-one named John.