Roger stated that an underlined "0" in "Co", usually indicated foreign made. It is not an absolute.
Unless the knife predates 1891, and foreign made, it should have a country of origin, although that might vhave been etched and long gone or the importers might have ignored the requirements altogether.
It's a beautiful old knife, regardless its origins.
DE OPPRESSO LIBER
"...Men may spurn our appeals, reject our message, oppose our arguments, despise our persons ___but they are helpless against our prayers. "