Those are slotted cleats. They were used by nearly all bike racers and many recreational cyclists for many decades. The slot slid down on the back of a the cage for a normal quill or rattrap style pedal. They were used with toe clips and straps and worked as well as today's clipless for ease of use and holding your foot onto the pedal.

The three mounting hole pattern will work for Look cleats. I can't tell if SPD cleats can be mounted to these.