Source of my info: The missing building I am referring to is shown in one of the sample photos advertising the TrueEarth Oregon package. See image below from the Orbx site. I'm not seeing the correct model. I'm seeing a very generic warehouse-looking boxy building in its place, rather than this unique blimp hangar.
The Tillamook Air Museum is an unmistakable building that can be seen from airport KTMK.
The size of my Oregon SD install folders:
Custom = 2.01 GB, 2188 files, 48 folders
Overlay = 1.54 GB, 6282 files, 91 folders
Orthos = 54.8 GB, 50041 files, 5 folders