There was no 4A violation in the seizure at all. The defendants had probable cause to seize the firearm (and accessories), until such a time that the DA decided not to try and prosecute Al-Mujaahid.
Until that moment, the property was evidence of possible wrong doing. After that moment, his property should have been returned.
Apparently, in other cases, all property is returned after disposition, unless it is firearms. That is the claim.