Circa 2002 In the early 1970’s, Rolex outfitted a special version of the 1675 with a Jubilee bracelet-making it the only sports model to be factory-fitted with this bracelet design. Apparently, this was an option until the early 1960s, but very few made it out of the factory without it, making this a bit of a rarity. Also on the 1675, the wording “Official Certified Chronometer” printed on the dial, was first changed to “Superlative Chronometer Officially Certified.”Īnother feature missing from early models was the cyclops lens, positioned over the date aperture. Like the Submariner, the early GMT models did not have crown guards to protect the winding stem-this feature was added in the early 1960s (on model 1675), and a more rounded version was outfitted in the late 1960s. Around the same time Rolex changed the wording at the bottom of the dial from Swiss to Swiss T<25, signifying the switch from Radium to Tritium as the luminous material used on the dial and hands. By the mid 1960’s, the extra function 24-hour hand switched from a small arrow on the tip, to a larger arrow. Note the tiny arrow on the tip of wheel numbers changed from ‘alternating’ red/black to all black. In the early 1960’s, Rolex changed the color of lettering Early GMT (model 6542) with Bakelite printed on the dial from gold to white, and with it the date bezel. Thus, black dials were issued to air crew, with white dials issued to ground staff. Apparently, Pan AM ordered a small number (probably less than 200) of watches with this configuration, to differentiate between watches intended for air crew and for ground staff. Another rarity for the early GMT was the presence of a white dial. It was quickly replaced with a metal bezel, making these early models quite desirable for collectors. This bezel was found to be inferior, because it had a tendency to fracture when in very warm environments. Early versions also featured an acrylic Bakelite bezel, which had a darker finish, so as not to be reflective into the pilot’s eyes. The earliest versions are easily identified because they are not marked “GMT-Master” on the dial, but instead have the depth rating “50m = 165ft” printed in red above the 6. In 1954, Rolex launched the GMT-Master (model 6542), after a request from Pan American Airlines for a watch that “could simultaneously display the exact time in two different time zones.” The watch was an instant success, and was adopted by Pan AM, as well as numerous other airlines worldwide, as their official timepiece.