I'll be curious to see what you find... Our 1992 Classis seems to have the same lock.
The Out of Doors Mart and eTrailer locks appear to be a similar replacement but not an exact match (for ours at least).
Have you tried contacting Airstream? If Airstream is not helpful, Out of Doors Mart sometimes has new old stock for some older parts. They helped me out on several items for our 1992.
Lucius and Danielle
1992 29' Excella Classic / 2010 Interstate
2005 Chevrolet Suburban K2500 8.1L
2018 GMC Sierra K1500 SLT, 6.2L, Max Trailering
Got a cooped-up feeling, gotta get out of town, got those Airstream campin' blues...