Yes. The designation of ”special duty area” dates to the sixties. The first reference to special duty area comes in 1965.
A challenge with Korea specifically is that the veterans of Korea were included in the war veterans acts prior to that, and then the special duty area was declared in the 1960s. We see multiple changes to that in various orders in council.
It was done through orders in council prior to a change in legislation, which provided the authority to the Minister of National Defence.