It literally is. It was created to enable what happened in the Militia acts of 1792 passed barely 5 months after the ratification of the second amendment. Namely, the requirement that the drafted Militia muster with arms they had to provide for themselves, with zero compensation for said arms or service. This is difficult to require if your people are forbidden from actually having said arms in the first place. And this is still valid today since every able-bodied male aged 17-45 is part of the official "Unorganized Militia of the United States" according to the Dick Act of 1903 (which also created the National Guard, AKA the "Organized Militia").