Serial Number Range: 875xxx-11xxxxx
Notes: The Type A non-chapter ring gilt dial is also called the “Swiss Only” dial by collectors. This can be explained simply: whereas the Type A dial has ‘Swiss’ at the 6 o’clock position, the Type C dial is marked ‘Swiss T<25’ at the bottom. As with everything Rolex, however, there is a not-so-simple exception: the Type B non-chapter ring dial is also been seen with only “swiss” at the bottom; as explained more thoroughly on that page, however, those single-swiss dials are always accompanied by an underline, whereas these Type A dials can come without other markings and be truly swiss only. Just to frustrate you further though, the Type A can come with an underline as well. Despite documentation of Type C “Swiss T<25” dials also starting around 875xxx, I think the Type C is a successor as this runs the latest and is identical to the font of the Mark 0 matte dial. Also, whereas the Type A/B are only seen in PCG cases, the Type C starts in PCG cases and are continued into the later rounded/shaped crown guard cases.
Looking at them part by part, the A and C dials are very similar. The only big differences to be seen (apart from the swiss text) are in the ‘oyster perpetual’ line where the Type A dial has very long letters that appear smashed together and the C dial has more even spacing. The easiest letter to spot the change is the ‘a’ in perpetual.