a short postscript on the gas door key:
i received the rumored third set of keys from my father, and these included two keys in addition to the door and ignition keys. the first candidate didn't fit the lock in the gas door, but the second one did. it was quite a surprise, then, when i turned it and found that the door would not open... i UN-turned it and, sure enough, the door opened right up; it had been unlocked to begin with! i never thought to try to open it, assuming that it was locked. oh well, now at least i have a key if i ever do feel like locking it.
the gas door key has Miraglio on its head (along with the number 6124 stamped in below), and Torino on the flip side. Miraglio makes components / accessories for cars even now, and is still based in Torino, where my car was sold new. based on when the car left Italy, i could guess that the lock was added to the gas door early in the 70's.
the remaining mystery key says "Lessi" on one side and Torino on the other. there is a furniture company called Lessi in Como... maybe i've got someone's dresser key?
-Jason