Nudge, I think some of it will depend on how -and where
If you are referring to the bottom of the barrels as pictured above that is a specific trademark. I believe I have seen papers previously posted by Dr. Drew Hause reference that trademark and proper usage. If you are referring to engraving on the top of the barrels Krupp Fluid Steel- Lefever Arms Co that is not the official trademarking and doesnt really have a convention. It also doesnt guarantee they are truly Krupp.