I read the note from Immortal Sun and inspired by his question I looked for a document I have received when I gave my VC Overseas Chrono 49140 to a complete revision to Vacheron in 10/2014 via Wempe Jewlery in Germany.
Unfortunately I do not have any orginal documents as I bought the watch from a working colleague a few years ago and he retired in the meantime.
At that time, I was not aware of the importance of such documents and was only astonished by the very nice watch.
Wempe gave me a paper where they say: Individual Number (in German) which is: 760448
It is also on the back side of my Overseas and I believe the English translation would be the "Reference Number".
Anyhow now my question: Is it possible to determine the birth date based on that number?
Thanks in advance and best regards