I'm not an expert on the Pan American Airlines GMT 6542 model. These are very rare and most reference books imply that fewer than 200 of these white dials were made and are an extremely rare find today. First the Pan-American GMT did not have crown guards, second the dial did not have the word "superlative" written on the dial. Also "officially certified" was below the words "GMT-Master".
The dial on your watch I do not believe is a Pan-American white dial. It is a puzzle and I do hope you are able to determine what exactly you hold in your hand.
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Link:
https://www.hodinkee.com/articles/Albino-GMT-Master-6542Click to expand...