I sold one of my G35's yesterday, it was a sad day... Anyway, while I was going through the case for the owners manual I found a key ring that had one of those plastic inventory tags from each of the the previous owners. I knew from the carfacts that there were three owners before me and each one of their tags from the dealership was on there. That was really cool, but there was also a tiny metal tag about the size of my pinky nail with a five digit number laser etched into it. What was that? Was that the pin code?