well, it wasn't in my z (I haven't found anything interesting yet)
But in my 62 vw ragtop, i found MANY bullet casing, from what looked like a 9mm pistol of some sort. no complete bullets, but lots of shells (at least 10 of them) they were hidden in the seat's sliding rails, and had been there for many years (nice and green on some bits) quite interesting to know that your car has bullet shells, when the p/o (me and my dad's friend) didn't own a single gun and has never in his life.
makes me wonder who used to own it o_O
i'm sure i'll find something in my z. the only thing i've found that was interesting so far is a bottle of brake fluid sitting next to the master cylinders for no reason, other than, it fits rather nicely and doesn't move around when you drive it! OH i know what's interesting. my spare tire!! it's just as heavy as a normal one, but, the treads are totally flat, and it looks like it was compressed. the p/o said it uses some sort of charger to fill it up to maximum capacity, and it's actually the size of a normal tire. I've never seen anything like that before o_O