Chuck, here's what I've kinda loosely come up with. Cursive lettering seems to have been used 1957-1963. The early 110-110A may have used a white tube crank knob in 1956. A sculpted black knob seems to have been used 1957-1966, changed to a sculpted white knob 1966-73 and a flat white wedge-shape 1974-5 to 1979.
The pushbutton looks to have been sculpted black 1956-1965, sculpted white 1966-1973, flattened white wedge 1974-5-1979.