How old is that nut?!

While shop vac-ing the truck I found a number of interesting items, but the best was this walnut:

It was behind the gas tank on the passenger side. I have no idea how long that nut has been back there. Walnuts are pretty tough, so I'm going claim that it made it's way back there in the 60's or 70's and has been waiting all this time for me to find it.

It's probably not that old, but its fun to imagine.