David,
my point of wiew is that we're talking about watches of different periods in a "not aesy" heuer lifetime.
The second Silverstone signed, that we've seen in Chronomaddox
http://www.chronomaddox.com/heuer/watches/wrist/silverstone/5012/SilverstoneRef.510.403_5041077819.pdf
of an ebay's 2005 bid, demonstrate that mine is not the only one produced.

: For what its worth, I have my Lemania Silverstone in front of me.
: My hands are like the example shown by Jeff at OTD, my crown is
: unsigned and there is no serial number between the lugs. I
: haven't opened the back, so who knows what is on the rotor, but
: my guess given what I mentioned above is that it will signed
: "Lemania".

: Fabrizio is the expert on the 5100 series- I have owned three
: myself (AudiSport, 510.501 and the Silverstone) and all of them
: have/ had the characteristics that Fabrizio mentions.

: I certainly agree with Bullitt's point that it was very hard to
: keep track of what Heuer where up to during that period, and
: while its not possible to rule out some inconsistencies in the
: production (some with signed rotors, some without), it is 100%
: clear that the majority of the 5100 series were not signed in
: all of the places that one might normally expect- and so to
: consider signed components as a definite sign of originality
: will lead to disappointment...