Correct me if I’m wrong but the 39 series is “drop safe”, but only when the safety is engaged. Unlike a 1911 where the firing pin is free floating and held to the rear with the firing pin spring (just as the 39 is with the safety disengaged) when the safety is applied to a 39, as the barrel rotates to decock the hammer and as it moves to the safe position and shields the end of the firing pin from the hammer dropping, a portion of the barrel also engages a notch in the firing pin, locking it in place to the rear. You can test this function by pushing the rear of the pin with the safety on and off and seeing it depress with the safety disengaged and locked in place with the safety engaged.