William Ross, received a British patent in 1893 that covered this iron—the first spring-face iron ever patented.
There is a cavity behind the face of this gunmetal iron head. Over this cavity is fixed a thin plate of steel, which forms the striking face. The cavity behind the plate, which is held in place by the three large bronze "rivets", allows the face to move freely, to act as a spring to impart added distance to the ball. At least in theory...
The shaft appears to be original, and the grip is possibly an old replacement, but fitting the period well.
TCA2: V2, p413