Ours has to be the only Airstream I have seen that has every lock keyed different. If you want to remove the lock, open the underbed access area, and remove the nut holding the latch on the lock. The access door should then be flopping in the breeze. Take the door to a locksmith, and have him make a key for it. If you are luckier than me, the one key will fit every lock except the main door, and potable water locks.
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.