It’s actually considerably better than the rule promulgated by the Bush Administration:
(b) Protecting the Right of Individuals To Bear Arms in Units of the National Park System and the National Wildlife Refuge System.–The Secretary of the Interior shall not promulgate or enforce any regulation that prohibits an individual from possessing a firearm including an assembled or functional firearm in any unit of the National Park System or the National Wildlife Refuge System if–
(1) the individual is not otherwise prohibited by law from possessing the firearm; and
(2) the possession of the firearm is in compliance with the law of the State in which the unit of the National Park System or the National Wildlife Refuge System is located.
That’s the right law. It would also protect lawful open carrying of firearms in states which allow it. There are some states, however, like Florida (Florida either fixed its law or I’m wrong about it), that prohibit possession of firearms in National Parks as part of state law, so you’re still screwed there until you can fix the state law. But for the rest of us, this is probably the best we could have asked for. Thank you Tom Coburn!