Hello everybody, after having seen both in person and in picture many examples of the 1000 series chronographs (510.500 polished, .501 black PVD etc.) I still am not able to understand whether these watches:

1- Should have a signed crown
2- Should have the "Heuer" stamp on the back cover

As said, I have seen both signed and unsigned crowns: unsigned seem to be the rule for the pewter version but no 'hard & fast rule' such as for the 510.511 & 23 Carreras seems to apply.

For the back cover, again both are to be found and I have seen both Heuer-marked backs on the 510.501.

I am also wondering whether these (lack of) signature indicates an earlier or later production run.
Maybe someone else has already pondered on this topic, but I couldn't find any hints on the OtD magnificent gallery.
Any tips?

Thanks in advance.

Fabrizio