I'd say from the faded paint on the doors, NPS service seems likely, it is the right shape for their door markings anyway.
Looks quite similar to this one from the Yosemite National Park archives, photo says Nov 1966 and it is parked in front of the Yosemite Valley fire station.
Photo credit Yosemite National Park
Looks quite similar to this one from the Yosemite National Park archives, photo says Nov 1966 and it is parked in front of the Yosemite Valley fire station.
Photo credit Yosemite National Park
Aaron Woods