Correct. No matter what the second amendment means, it only applies to the federal government.
So if a state, today, confiscates all weapons from its citizens and stores them in a secure state armory for use by the citizens when needed, that would not violate the second amendment (or any other part of the U.S. Constitution). Yes?
So, how does the second amendment ensure that citizens "would not be barred from keeping the arms they would need when called forth for militia duty"? It doesn't.
No, because the 14th Amendment has been interpreted continually to mean that the States can't violate constitutional rights.
But the fourteenth is a cesspool. Texturally it imposes anything the feds want on the states. It's original intent is murky, with broad statements by it's enactors. What little I've seen of the ratifying debates in the states - the determining evidence per Madison- points to it's purpose being to end discrimination of rights instead. But the evidence is not clear to me at this point.
That issue wasn't decided by this court. But the language of Section IV of the opinion indicates that this panel of judges, if faced with the issue, would likely incorporate the Second Amendment to the States.