There is an interesting piece available for purchase on the bay, a beautiful Rolex Caliber 618. This movement was made by Cortebert and refinished/reworked by Rolex. It was featured in their pocket-watches as well as the early Rolex-made Panerai's such as the iconic 3646. I have seen many Cortebert 616 movements available for sale. I even own one, but a 618 which is essentially a 616 highly-refinished and branded by Rolex is super rare.
Video Below: Cortebert 616.