Hi, what (I think) I know so far:

In the beginning Carrera watches were delivered with unsigned crowns. On later Carreras the crowns were signed with Heuer.

Few questions about that topic:

- Was the diameter / thickness of the unsigned crowns different from the later ones?
- Had all first ex Carreras the unsigned crowns or changed Heuer the crowns during the production time of the first ex?
- If yes can the beginning of the change be specified by serial numbers or production year?
- Is there a write up on this topic or the sizes of the different crowns ( diameter, thickness, tube, stem)?
- Does someone know a crown (generic or contemporary) which looks quite exactely as the original one and could be used for replacing an unsigned original crown?

Please email me to chriswatches@gmx.net or post here

Any kind of help is highly appreciated, thanks for your time!