From what I understand, all 12 valve engines run the risk of the pin working it's way out, and 24 valve engines up to model year 2000, it's hit or miss. If you fall into these catagories, I would have it taken take of, it's cheap insurance. Good luck. BTW, there are no known serial numbers to use as a reference/guideline.
Rob
Moderators: could you post this in the correct forum.