My 96 Mystique that had a keyed glovebox had TWO keys, The second one was the glovebox and the trunk. My 99' SVT has just one. Also someone may have put a different lock on the trunk for their OWN reasons and didn't give it to you , or the dealer you got the car from. You can remove the lock yourself, and have it "rekeyed" for about $10 from a car lock place.
