For those interested in learning more about the history of firearms regulations in National Parks, the National Park Service has made available on a pdf website a document that covers this topic.
It is interesting to note that there were no uniformed regulations that affected all National Park Areas until 1936. Prior to that time regulations were approved for individual parks. The first recorded regulation that prohibited the possession of uncased and loaded firearms in a National Park dates back to 1897 in Yellowstone. This predated the National Park Service (est. 1916) and was enforced by U.S. Army Troops stationed in the park.
If you are interested in learning more, you can go to the site at: