Interesting topic. Over the years, 1960s - 2000s I use to go to Gun Shows and saw various firearms with CD markings as well as State or County markings.
The Office of Civil Defense, Regional Offices were abolished on July 1, 1944, due to the change in the war situation. Region IX was comprised of the region office, located in San Francisco, California, which served Arizona, California, Idaho, Montana, Nevada, Oregon, Utah and Washington.
Now we have CERT* (or at least in CA)
*Studies in World War II showed that lightly trained (40 hours or less) civilians in organized teams can perform up to 95% of emergency activities when trained, liaised and supported by local government. In this plan, the populace rescues itself from most situations, and provides information to a central office to prioritize professional emergency services.