Site doesn't seem to work in Firefox 4.0.1 Rich, I just get the side menu and everything else is black, regardless of what I select on the menu. Same for the Monaco site.

I'm sure Jeff is referring to what appears to be two blocks of numbers set aside for specific models before the Silverstones, and one very definite one after, as well as the range for Silverstones themselves. It does look like that range was blocked out for Silverstones - I have no other model's serials within it and I don't think Jeff has either. It definitely looks like Heuer was blocking out by model at this time, which they weren't necessarily doing before and after (at least not to the same extent), which also has some implications for dating any given watch - just makes it more difficult than ever!

Let's see what Jeff has to say on the subject when he publishes his piece :)