On ours, they aren't. We have four different keys, using different blanks, for ours (door, battery, water fill, back compartment). Kind of annoying! I assume this is because they use off-the-shelf locks for each spot, so there's no relatively inexpensive way to standardize. A previous owner etched the purpose of each key on it.
Is it a matter of you just not having the key (as opposed to a broken lock)? If so, try to find someone nearby with a similar Airstream, or call Airstream - you might find their key will work. Turns out a lot of them are the same...
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel
Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab