That's interesting but it will not sway the anti 2A crowd one inch. Their chant will always be more laws.
Maybe he would have still been able to find a gun and commit the crimes and maybe he would not. I think the point here is that the Federal Govt cannot operate any systems, departments or branches with any sort of success. Their failures are everwhere, 21.5 million identities stolen, back ground checks that do not work, Guns run into Mexico, Welfare fraud and abuse, the list goes on and on.
NCIC records will show you a lot about arrests, but they don't often tell you much about pleas/convictions. It's been getting better slowly, but it's amazing how much stuff people get arrested for that never shows any resolution added following prosecution. Some states are better than others with this, and I find LA has gotten much better over the last five years or so, especially with entries to show probation/parole status/dates.