In 1964 Winchester changed several things about the Model 94 to cheapen manufacture, which also cheapened quality.
One was the switch to a sintered metal (sorta a cast process) in place of a forged steel frame.
The new process metal wouldn't take conventional bluing, so it was iron plated, and the iron could then be blued.
The result was a finish that didn't hold up well with use & frequently ended up wearing off or rusting. Or both.