And here's the history of the watch, taken from James Dowling's website:
Due to Pan-Am.'s ever increasing fleet of Boeing 707s the vast majority of the early watches produced went to the company, each plane had a Pilot, a First Officer and a Navigator all of whom were issued with GMT Masters and Pan-Am had several hundred crews all issued with a company GMT Master.
These watches bore no company logo; no "Property of" markings and no special dials, apart from one strange bunch of 100+ watches made in 1958 especially to solve a problem inside the airline's Chrysler Building head office (they did not move to the new Pan-Am building until the early 1960s).
The problem was simply that as the watches arrived in the head office before being sent off to the field offices for issue to the flight crew, they would be requisitioned by senior management who felt that they, rather than the flight crews, were the ones who deserved a new company Rolex.
This happened on a regular basis until one day Juan Trippe, the mercurial head of Pan-Am glimpsed one of the watches on the wrist of an executive and wanted to know why it was not on the wrist of a pilot. The situation was explained to him; the pilots had everything, the gold braid, the titles, and the brand new Boeing jets and now they even got great watches.
The executives felt shunned, they saw themselves as the basis of the company's success but were fed up of being treated as second class citizens. Trippe did not like the situation and ordered that all the GMT Masters in the building should be returned to the operation department for subsequent issue to flight crews.
However to mollify the executives Trippe had Rolex manufacture a batch of 100+ GMT Masters solely for the "desk pilots"; these differed from the flight crew (and all other) GMT Masters in that they had white dials. They are believed to be the only GMTs made with this colour dial, the order proved a godsend to Rolex as they made these watches in 1959 with the last of the old model 6542 cases; for the new model was waiting in the wings.