Serial Number Range: 50xxxxx – 59xxxxx
Notes: Mark 5 is a complicated one (because the rest are so simple) as there have been 3 sub-species noted, which have been designated 5, 5A, and 5B. There isn’t a clear SN range for each of these so they are all lumped in together, at least for now. Some early serials have been seen with Mark 5 dials so they may have been service dials if the watches were serviced in the 1970’s, but this is not a common service dial. Credit again to springer for seeing these and showing them to the community.
Mark 5: The Mark 5 upper dial is differentiated by the coronet, which is slightly shorter than that of the Mark 4, the R of ROLEX, which no longer has the bloated right ‘leg’ of the 4’s but is now smooth, and the O, which is no longer circular as on the Mark 4 and looks very close to the radial dial text with less prominent serifs. The lower half of the dial looks similar to the Mark 3 with serifs and narrow O’s but is less svelte and has a large space between the R and O of chronometer.
Mark 5A: The 5A dial is differentiated from the 5 by the thinness of the text, a more slender coronet (more like the Mark 4), a wider top to the A of ‘GMT-Master,’ and slight changes in the font spacing. Additionally, whereas the Mark 5 dial is make by Beyeler, the 5A is made by Lemrich. Springer has a nice set of pictures of these two side by side here.
Mark 5B: The 5B dial is set apart from the previous two dials by the shape of the O’s throughout the ‘oyster perpetual’ and SCOC text – unlike the above dials where their shape is vertically ovoid, they are round on the 5B. Otherwise, the coronet is very similar to the 5A and the lower horizontal bars of the F’s in the SCOC text are longer than the above dials. Maybe we can call this one the ‘long F.’ See another example of this here.
Picture Credit: HQ Milton (5 and 5B), Lucky from IG (5A)