I'm not addressing whether the law is Constitutional.
I am saying ONLY that if they want to enforce it they are not currently empowered...nor are they likely to ever be...to go kicking down doors based on a list of background checks.
Do not think for a minute that I'm advocate for this law, nor for any LEO that is corrupt enough to attempt enforcement. No do I believe that it's legal under the Constitution.
Sorry if I misunderstood your post.