Hi Laurent - I've been reading this post with great interest as this is such a fascinating watch. I did notice a dial variation between these two examples. The register at 9 is single tone blue in the early example and two tone in the later piece (assuming early and later is determined by the style of hands). Just a small point but something I would never have noticed a year ago but with all my training, I do now.
Regards
Paul
www.heuerworld.com

: this one

:

: and this one

:

: are they both "factory" correct ?

: This amazing watch is a puzzle to me and I'd be happy to understand
: it.

: Thanks, Laurent