Rolex 1603 "Prototype" DatejustIn the late 1960s, Rolex began exploring fresh design horizons. Instead of using their in house dial makers, they commissioned Singer a Swiss firm celebrated for crafting the iconic Paul Newman Daytona dials, to produce concept dials that pushed aesthetic boundaries. Among these design experiments was a standout dial for the Datejust series: the rare blockmarker prototype dial, AKA the Singer block markers dial. This dial features elevated, mirrored