Thunderbird Billet Door Lock Pins – ‘Knob Top’ Style. NEW ITEM! – Billet Style Door Lock Pins! Replace your plain black plastic door lock pins with our stylish pins and add a custom flair to your Thunderbird. Made of lightweight billet aluminum and featuring a ‘knob style’ top. Our billet door lock pins are tamper resistant and easy to install … just unscrew the old ones and twist the new ones into place. Set of two. Made in the USA. In stock and ready to ship.