Rolex 1600/8 from late 60s

[Antoinerob]

Hi there,

I just bought this lovely gold datejust (1600/8) from the late sixties and I am very happy with it.

I have a few questions which I hope you can help here:
- Serial number is 1,822,xxx: Production date in '66, '67 or '68?
- Box: Which box reference belongs to the late gold datejust?
- Dial variations: Does anybody know what kind of dial color/indexes were available in the mid late sixties for such model.

Picture attached

Thanks!
Antoine