A good many people interested in vintage knives think and say that a line under the “O” in “CO.” Means the knife was definitely made in Germany.
While that may be true for many, many knives, it is not definitively true for all of them.
Your knife may very well be a German product, but that line, by itself, does not make it so. And given the “U.S.A” on the tang, I suspect not.
Some German makers were not averse to marking a knife with something other than its actual country-of-origin, especially around the time of WWI.
I have never seen nor heard of that tang stamp before.
Can you actually discern “ STEEL EDGE” in that stamp, because I cannot?
DE OPPRESSO LIBER
"...Men may spurn our appeals, reject our message, oppose our arguments, despise our persons ___but they are helpless against our prayers. "