Ferrari 328 Build date.

[JMDVAN]

Hi,
I am trying to pin down the build date of a 1987 Ferrari I want to import. But need to find out the build month before I import it. To see if it's over or under 30 years. Any idea's. I used the VIN decoder but that only narrows it down to year. I need the month. A build sheet or something like that?

Any idea where I could find the information?
Thanks