Hello Matthew, the winged pump does turn up with the black plastic knob on it, but in my experience the brass knob is more common. The chromed Guardsman pump usually has that black knob on it, but Tilley were always tinkering with their products, as these pump photos show, Jeff.
Ahhh I see. I might change my plastic one then it is a bit damaged so a brass one would look better. Regards Matt