Early 66 movements have screw on knobs, later they are staked.
Alarm Set Knob Fastening Threaded (screw-on):
The knob screws on, and there is a brass flat washer, a nut, a flat brass washer, and a split steel washer between the tension spring and the knob. Note: clock models with back alarm set dial always have the screw-on knob, and the alarm hand takes the place of the rear brass washer. Used through ca. early 1935.
