Serial Number Range (Mark 6): 55xxxxx – 59xxxxx
General Notes (Mark 6): The Mark 6 dial was formerly referred to as the “Mark X” dial as it was initially thought to only be a service dial. Later, it was determined to also be a production dial used at the very end of the 1675 model line. Today, these dials are considered original to 1675s with >5.5m serial numbers. When found on much earlier watches, they are considered early service dials, likely installed in from mid-1970’s to early 1980’s.
- The Mark 6 has the tallest coronet of any matte dial 1675 and is the easiest way to recognize a Mark 6. Compared to the Mark 5, which has the most similar coronet, the base of the Mark 6 is also more circular and small.
- The serifs of the ‘Rolex’ text are not sharp angles on the L and E but are smoothed curves.
- The ‘Oyster’ and ‘Perpetual’ words are spaced closer than the other dials and lack significant serifs.
- The lower text is best differentiated by it’s smooth G of GMT (which lacks the extra vertical line on the lower right) and the O of officially, which runs slightly lower than the rest of the SCOC text.
General Notes (Service Only Dials): There are both early (Mark 6) tritium service dials and late service tritium, luminova, and superluminova dials for 1675’s. For the later, service only (not production dials), there are simple tells:
- The later service dials (tritium, luminova, superluminova) have much squatter coronets with very crisply delineated lume plots.
- The luminova and superluminova service dials don’t use tritium so they don’t have patinated lume plots.
- The luminova dials have “Swiss T<25” at the bottom and the superluminova dials have “Swiss.”
Picture Credit: HQ Milton