When Rolex 1675 model replaced the original GMT-Master model in 1959, the company introduced some notable updates to the then-new model. First, the 1675 GMT-Master got a crown protector – a detail that was lacking in the previous model. To accommodate the new shoulders on either side of the winding crown, the 1675’s case was increased by 2 mm to a diameter of 40 mm. In addition, another important change made by replica Rolex is the replacement of the bakelite bezel of the old 6542 with an aluminum bezel on the GMT-Master 1675.
Since Rolex produced the GMT-Master 1675 for 20 years, the replica watch has undergone a number of changes throughout its history. For example, early examples of 1675 had pointed crown guards (known as PCG or El Cornino), which eventually evolved into the more rounded guards we are familiar with today. In addition, the Ref. 1675 changed over time; early examples were equipped with a lustrous gold-plated dial that featured a shiny black dial with gold lettering. Starting in the mid-1960s, the company moved to a matte black dial with white text. Rolex also added the option of an all-black 1675 bezel in the early 1970s, alongside models with the iconic blue and red “Pepsi” GMT-Master bezels.
Finally, Rolex has also updated the movement inside the GMT-Master 1675. The first movement to power the reference 1675 was the 1565 caliber, which ran at 18,000 BPH. By the mid-1960s, this movement was replaced by the 1575 caliber, whose frequency was increased to 19,800 BPH. In 1971, Rolex added a hacking function to the 1575 caliber that allowed the seconds hand to pause while adjusting the time. 
This particular GMT-Master 1675 is a later model, made in the late 1970s. Its dial is matte black, and its tritium luminous pattern has been transformed into a warm cream shade. In addition, it has what collectors call a Mark 5 dial, defined in part by the vertical line to the right of the M in “Master” aligned with the middle of the C and H in “Chronometer”.
But it’s the detail on the dial, just above the indexes at six o’clock, that makes this GMT-Master 1675 particularly noteworthy. An AB logo sits above the GMT-Master name, which makes this a co-branded dial. The AB logo comes from the Arkansas Best Company (now renamed ArcBest Corporation), which was founded in 1923 in Fort Smith, Arkansas, as OK Transfer, a local freight company. The company was incorporated as Arkansas Best in 1966 and became a public company listed on the New York Stock Exchange in 1972. We can only assume that the company issued these AB marked Rolex GMT-Master 1675 co-branded examples to its longest-serving personnel.
The bezel is the most recognizable attribute, with its signature blue and red Pepsi color scheme, which was replaced at the time of service, giving the fake watch almost as original an appearance as when it was made nearly 40 years ago. It may be a pilot’s watch, but the GMT-Master’s legendary toughness and resilience make it a logical choice to honor the needs of the transportation industry.
In addition to the GMT-Master 1675 with the AB logo we highlighted above, Rolex made many other examples of the same model with different co-branded dials. The most famous of these all is the double-stamped Tiffany GMT-Master 1675, with the Tiffany & Co. logo above the GMT-Master name – retailed exclusively at select Tiffany boutiques, of course.
There are also vintage GMT-Master 1675 models bearing the official insignia of Middle Eastern countries such as the United Arab Emirates and Oman. These double-stamped copy Rolex watches were often worn by government, military, and police personnel, or given as gifts to civilians by their leaders.
The co-branded dial segment is a fascinating corner of the vintage Rolex market – some collectors focus on researching and accumulating them. the AB branded Reference GMT-Master 1675 is just one fascinating example of a large number of other double-stamped Rolex dial examples.
