Also Camaro uses all signed crowns since the watch introduction.
Yes, but the Camaro doesn't appear until 1967 at the earliest, so there has been 3 years of Carrera production at that point. It could well be that that point is when Carreras all started to be fitted with signed crowns too, but the Camaro introduction isn't otherwise significant for Carreras (there's not a step change in dial for example) so for clarity it is easier to take the significant changes that come with the introduction of the Carrera 30 and use that as the cut-off point.

What do you mean with second generation Carreras, for me the second
: generation starts with the product changes after hexacase,
: pushers, dial...
We discussed this when we were putting the table together if you recall. We take the first execution as all Carreras with simple steel markers and hands and second execution as those with inserts for markers and hands, which coincides with the introduction of the Carrera 30 circa 1969. Second execution also encompasses the significant change to the tachy scales and the colour change for the deci scale.

Yes, there are some detail changes before that, but they don't all occur together and we would just end up with a confusing number of executions if we raised each change to the level of an execution change. I think of it more as the Carrera evolving over that first execution. The dodecagonal (yeah, that's why I call them polygonal) caseback was clearly just an interim measure that was soon phased out in favour of the "proper" Carrera caseback. The border that carries the tachy/deci/pulse scale becomes more of a discrete band from the rest of the dial. The distinctly silver finish of an S dial becomes a more matte whiter finish.

Trying to put an accurate date on each of these would be extremely difficult, exacerbated by the number of watches that are effectively interim from one to the other - there is not the distinct step from one style to another that we see from what we have defined as first execution to second execution. So in the end we decided to be pragmatic and group them in just those two executions. Even then we ended up with 51 discrete "models" for the first generation Carreras.