When you said, "It was a foreseeable and intentional act on the part of the Supreme Court to allow INDIVIDUALS to be acquitted SOLELY on the basis of whether the arms they possessed were useful to a militia", you were painting with a very large brush. You were impling (I think) that their membership in a Militia was irrelevant.
I was merely wondering out loud how your statement would hold up if there were other factors barring Miller and Layton from owning a gun (eg., IF there was a law in 1938 barring felons from owning guns).
It was actually the Miller Court which was painting with a very large brush. Any legislated limitations on the right to keep and bear arms that satisfied "strict scrutiny" would be in little jeopardy. I doubt that that such limitations were in place, though.
Hollywood is not necessarily the best source on legal history, but I recall one movie depicting a bank-robbing felon on the run purchasing a shotgun in a hardware store probably in the sixties. There was no consideration of whether the man was an escaped convict, felon, or legally insane. It was pretty obvious that the man was older than 14.
Most of the prior restraint laws were passed in 1968, I believe.
Such charges would have to have been brought and there is no indication that the District Court judge considered anything other than NFA 34. Even today, felons are not charged with possession of a firearm in cases where they sought the firearm in an act of self-defense from a lethal attack. It's similar to the problem of trying to charge people with failing to register an illegal gun. You can't violate a person's protection from self-incrimination. Similarly, you can't violate a person's right to defend themselves from a lethal attack.