Date on Solex aircleaner housing + Number on solex carbs

Can anyone tell me more about the date stamps on the solex aircleaner housing?
These are always like X/65.
Is there also a difference with those without date?
Where they use both? At same time? Mixed used?
Where the ones without date older? Belonging to 64cars?

And what are the numbers on solex carbs? There are numbers next to the words solex.
They are always stamped vertical...
What does these numberd mean? Specific to a car? Or just production?
Is there a time table?


Please tell me more...