Anche io ho trovato questa indicazione:
I think that the complete VIN is stamped on the top right rear portion of the frame just above where the upper control arm attached to the bracket. Probably very hard to see if there is a lot of dirt and maybe rust.

My 87 has the last 8 digits of the VIN stamped on the front of the frame directly in front of the stock battery location. It's H (for '87), 5 (for Bowling Green Assembly Plant) and the last 6 is the sequential build number.

I had to remove the lower rear portion of the wheel well to see it. The 10th digit of the VIN is the year so the first digit of the last 8 will be the year.

Siccome ho ancora la macchina mezza smontata, stasera do un'occhiata anche io.