I'm with you on this one Andy, I think the 158s are genuine. The transitional that I first owned back in 2000 had a very even (and quite heavy) patina of age with correct dial and hands. There was no reason think that it was anything other than original and it's serial was 158 1XX and back then the value wouldn't have created quite so many Frankenstein watches (I paid £540 for it) It came from the US so could be one of the fabled 12?

As for looks? In spite of it's rarity I didn't like it as much as the flat blue dial version (the hands were particularly ugly and ill proportioned which would explain why Heuer changed them) so consequently it now sits on a famous film star's wrist and I used the money to buy a flat blue Monaco and a Siffert Autavia.