Fourth Amendment Violation in Police Policy of Test-Firing All Guns They Get, Even With No Individualized Suspicion?

From the Fayetteville Observer:

George Boggs thought he was doing police a favor last week when he handed over the firearm he kept in his car after he was in a wreck.

Boggs has a permit to carry a concealed weapon, and he wanted his handgun secured while he went to the hospital, he said. The permit requires him to notify police of his weapon. On Monday, when he went to the Fayetteville Police Department to retrieve his gun, he couldn't get it back. He was told that police first wanted to fire the gun to see if the spent shell casing and round would match data in a nationwide ballistics inventory used to solve crimes.

The gun is scheduled to be test-fired today, he was told.

Boggs complained to police supervisors that his new gun has never been fired. The ballistics test, he said, would diminish the value of the .45-caliber Taurus Millennium he bought last month for $399 at a local gun store.

He said the city is violating his Fourth Amendment rights that protect him from unreasonable searches and seizures.

Police defend their decade-old policy of checking most handguns that come into their custody -- no matter the reason -- to see if they have been used in a crime. They say public safety outweighs any inconvenience to the owner.

My tentative thinking is that any such policy of test-firing all guns that come into police custody, with no individualized suspicion that the gun had been used in any misconduct, violates the Fourth Amendment violation. It's a search, at least as much as moving the stereo equipment to see the serial number in Arizona v. Hicks was a search. (Hicks was a Justice Scalia opinion, by the way.) And it's hard to justify this under the special needs / administrative search rationale, because it does seem to be aimed at serving the general interest in law enforcement.

To be sure, this search is much less intrusive than many other searches, and it doesn't outrage me (though note that I'm generally far from a privacy maximalist). Still, it seems to be prohibited by standard Fourth Amendment doctrine. Or am I missing something?