Not really. They found that they had no evidence before them that a sawed off shotgun was a suitable weapon for a militia because Miller was dead and his lawyer didn't bother to argue before the Court.
The first is almost correct, the second is not. The Southwest American reported on April 6, 1939, that Miller's body had been found in the "nearly dry" bed of Little Spencer creek, nine miles southwest of Chelesa, Oklahoma. He had been shot four times with a .38. Miller's ".45 calibre pistol," from which he had fired three shots in his defense, was found near his body. The case was argued March 30, 1939. - Decided May 15, 1939. Of course Miller could not be located, and the lawyer wasn't about to go to the expense of a Supreme Court appearance, or even just a brief, with no paying client.
However Miller's codefendant Layton was found, at least after the Supreme Court handed down it's decision. He plead guilty and was given probation by the same judge who had originally thrown the case out on the grounds that the law violated the Second Amendment.
The government however thought the case important enough that the Solicitor General himself was on the brief, although he did not present the case.
The Court did not find that *they* had no such evidence, but rather that the original court in Arkansas did not, and thus should not have ruled that the keeping and bearing of such a weapon was protected by the second amendment.