In 1980, Steven Spielberg and George Lucas were working hard on the casting for Raiders of the Lost Ark. At the top of their list for the lead role was Tom Selleck, who consistently outperformed all other actors in auditions. Dressed in a brown WWII-era leather jacket and a tan fedora, Selleck was everything Lucas envisioned Raiders of the Lost Ark to be. Everything seemed to be on track until Spielberg got a call from the president of CBS. The network had signed Selleck to a contract for a new series, and Spielberg couldn’t have him. The show, of course, was “The Hurt Locker” – and a different man filled the role of Indiana Jones.
Fate’s intervention was appropriate. Selleck was born to play Thomas Magnum, the aloha-shirted private detective who works in a luxurious estate on Oahu. His hair, majestic build, and beard are the pillars of the 1980s style. Selleck remains the poster boy for the era. 
Over time, it has undeniably become Magnum’s symbolic watch, but it wasn’t always the one on his wrist. It didn’t appear until the show’s fourth season. For most of the first few seasons, he wore the Chronosport Sea Quartz 30, “a chunky 42mm dive watch with a bright dial and tropical rubber strap,” as Jason Heaton described it. For the Seiko heads out there, Magnum even occasionally wears a Seiko S.Q. quartz dive watch with a red and blue bezel – you know, when he needs a more dive-friendly Pepsi watch.
So, why is the replica Rolex GMT-Master the perfect Magnum, P.I. watch? For starters, it’s a watch that matches competence and rugged charm with a bit of whimsy and color. It’s a 100-meter water-resistant dual time zone watch with a steel bracelet, so it can hold up well in a surf splash while tracking the time on the continent. It’s the epitome of a tool watch, but the red and blue keep it from getting too serious. Because no matter how much ass Magnum kicks, he does it with a smile on his face.
With all the attention paid to the watch, there has been some debate about the model worn by the GMT-Master Magnum. For years, the word on the street was 1675 – a variant of the classic matte dial produced from 1959 to 1980. After some investigation and searching for direction, we can safely say this is a reference 16750. Its the successor model to re. 1675, produced from 1980 to 1988 – the same time frame as the series’ run. Coincidence? (Well, maybe).
Two details explain why this is a GMT-Master 16750: the crown protection and the order of the dial hands. As Jon Bues and Eric Wind point out in their reference point on the GMT-Master, the 24-hour hand on the 16750 is between the hour and minute hands. On the ref. 1675, on the other hand, the 24-hour hand is located at the bottom, closest to the dial. Next, the 16750 has unique crown protectors (at least in the matte dial variant) that are pretty different from any other GMT-Master model. They are significantly higher and rise above the crown. On the ref. 1675, the crown occupies a more prominent position, while the crown guard is much shorter.
The ref. 16750 is a more comprehensive watch than its predecessor. Firstly, it is water-resistant to 100 meters instead of 50 meters. The ref. 16750 is the first fake Rolex GMT-Master with a quick-set date function. Magnum did not have time to rotate the hands on his watch to change the date.
So it is becoming clear why this was the perfect watch for Magnum, but there is one reason above all others. It’s his father’s watch. That’s right, in the show’s canon, the Magnum P.I. Rolex GMT isn’t just a watch. It’s an heirloom, a keepsake, a memento of Magnum’s late father.
In a flashback in the season four premiere episode, a young Thomas Magnum swims with his father in the ocean. In the water, his father takes a moment to refer to his watch as he times his son’s swim. The camera is glued to the GMT 16750, with its matte dial, Pepsi bezel, and bright white markers. Folks, this watch has no patina.
Of course, there is a bit of suspense here. Suppose you did the math (and don’t do it because it will frustrate you and hurt your brain) when Magnum was a little boy, the ref. Rolex hadn’t made sixteen thousand seven hundred fifty yet. It was first introduced the same year the show started, so it didn’t exist. But this is television, and the normal laws of time don’t apply.
The GMT-Master 16750 is the most typical GMT-Master (and Rolex steel sports copy watch). Nowadays, as the value of this model has risen, you’ll find some versions with light bezels in all sorts of odd colors and markers with a heavy patina. In the show, it’s ever-present in its proper era, frozen in time – helping Magnum defeat the bad guys and close the case.