I ended up with an extra key for BF lvl 1. Don't know if this is another random generated possibility or not. Also the number of dungeons doesn't seem to be only three. Act II has 6 dungeons in it. I've found two keys for lvls 1 and 2. I always pick them up though I read you don't have to do this. I don't recall now if I get the meassage that I can enter a dungeon when click on the key on the ground or when I drag it to my inventory. I'm pretty sure it is only when you first click on it though.
