You can apply for the certificate online, via a form on their website.
https://www.volkswagen-classic-parts.com/shop/en_global/volkswagen-certificate.html#anker-form
We need to know the chassis number of your vehicle, the name of the
vehicles' owner and the complete address where we should send the certificate
to.
Volkswagen Classicparts
And you will
receive a nice document which states:
Build date, delivery date, destination of delivery, along with the original colour of the paintwork and interior and any factory fitted extras.
Build date, delivery date, destination of delivery, along with the original colour of the paintwork and interior and any factory fitted extras.