Use a good magnifying glass. Look at the bottom of the engraving valley/cut. It will show steps or variable depths of the cut, if it was made using a hammer. It is not smooth.
Using a good magnifying glass on engraving can give good clues to determine if engraving is factory or aftermarket. If you see oxidation /pits IN the engraving, it is "factory.". If you see engraving cuts THROUGH pits, it means the pits were there first, then engraving occurred LATER ( NOT factory original). This is just one clue to input into the decision ( others include: bluing condition, washed out/thin stamped letters and numbers, drilled/tapped holes. These indicate " tinkering" , and if one thing is messed with likely other things are "not right"- to be polite.) It is not absolute. I used to run the firearms division at James D. Julia auction house. I learned this " magnifier/pit/groove evaluation technique from one of our firearms consultants (Frank Sellers, who wrote a great book on Sharps Rifles:
https://www.amazon.com/Sharps-Firearms-Frank-M-Sellers/dp/0960812202.), to know how to spot fake " factory engraving," and other clues for being "altered."
