dual colored bezel?

[BiG JeEzY]

Originally Posted by Spacedweller

It is to tell the AM/PM difference as the GMT hand moves around the dial.

Yes it is a way to tell between AM and PM differences.

Since the Explorer II and GMT black bezel dont have dual colors, the way to tell AM and PM with those is to always know the idea that any number from 0 to 12 is AM and from 12 to 0 is PM on the bezel.

That idea works for all the second timezone watches actually.

[BiG JeEzY]

Originally Posted by mike

The white 6542 is about as collectible as it gets. LOL! So few were ever made. I'm aware of one that changed hands privately.
If I had to guess I'd say it's north of 100K,

I agree with Mike, it would probably be over 100k

[Flyjet601]

Originally Posted by mike

Studying these wonderfull pieces and the rich history of the company is indeed half the fun of all things Rolex. Often we look at Rolex in the microcosm of the here and now.
Historically, Rolex has led the way in several fields of endeavor, the history of the GMT being only one.
The article you refer to is a great start! Here's another, with a few pics, (note: the author borrowed heavily from the article written by Mr. James Dowling that you cite).
http://www.fiftyfathoms.net/Rolex/6542.html

Other great bits of information on the GMT can be found here.
The author is a wonderfull gentleman and extremely knowledgeable in all things GMT.

http://www.doubleredseadweller.com/

As with most everything Rolex, new information constantly comes to the fore. Certainly the printed word is a valuable tool, but IMO some great internet sites have proven to be the real nexus of study and learning as collectors share the wealth of their study.

As usual, great info Mike