Porsche certificate of authenticity document

[foibles]

I have a 1989 porsche 928 s4... And i need to prove both its month and year of manufacture to my local vehicle regulator.

Im not sure if a PCOA provides this detail... I'm not sure what a PCOA costs... Or how i get one... Or how quickly i can be sent the results... Ideally I'm after this detail asap.

Can anyone assist or provide direction please?