Steve,
I believe the Act under which the summit hut is protected is more likely the National Historic Preservation Act, which would make it a federal matter. I could find no "Natural History Preservation Act" for California or elsewhere.
Here is a link of the Act, as amended through 2006, which seems to be the latest amendment (I even got to update Wiki's External Links section with this link, since their current link only had the Act as amended through 2000):
NHPACaT