In principle, you're right. But, for the rest of this guy's life he will have a file on him at the SS and the FBI. Regardless what the SS says to the man, he will forever be on a "watch" list of sorts.
Would be interesting to see what happens with his Form 4473 and NICS should he decide to purchase a firearm.
I can promise you that a) the SS were fully aware of any and all "registered" firearms this man may have had prior to their arrival. and b)The SS will be "aware" of any future firearms purchases by this guy.
That's why I'm against the registering of ANY constitutionally protected weapon. We don't register books we by, do we?