Um.. This is long over and done. Because of this, the Federal Government and many States have enacted laws to stop this from ever happening again. The NRA was all over this the second it happened.
from the NRA wiki:
Confiscations in New Orleans
In the aftermath of Hurricane Katrina, multiple reports of confiscations of civilian weapons by law enforcement began coming out of New Orleans. Warrantless weapon searches of evacuees were carried out prior to allowing them into evacuation centers[14], unconstitutional house-to-house weapon confiscations were reported,[15] and the superintendent of police was quoted as saying "Only law enforcement are allowed to have weapons" and "We are going to take all of the weapons"[16].
On September 12, 2005 National Rifle Association executive vice-president Wayne LaPierre spoke out against these confiscations. "What we’ve seen in Louisiana — the breakdown of law and order in the aftermath of disaster — is exactly the kind of situation where the Second Amendment was intended to allow citizens to protect themselves," LaPierre said. The NRA filed suit in the United States District Court for the Eastern District in Louisiana.
On September 23, two weeks after seizures began, NRA and SAF filed for a temporary restraining order. On September 24, 2005 U.S. District Court for the Eastern District of Louisiana issued a temporary restraining order barring any further gun confiscations and ordering the return of lawfully owned firearms to their owners. On March 1, 2006, the NRA filed a motion for contempt against the city of New Orleans, its mayor, and the chief of police for failure to comply with the restraining order. On March 15, 2006, lawyers from both sides reached an agreement in the case of NRA v. Mayor Ray Nagin, which is pending before a federal court. The city of New Orleans admitted that it holds a number of confiscated firearms, and the Property and Evidence Division of the New Orleans Police Department is to return the firearms to their owners on request and proof of ownership or affidavit. In the chaos and destruction following Katrina many homeowners have, however, lost everything including the paperwork that would prove ownership. At this time (2006) the majority of the seized firearms have not been returned to the rightful owners. (See Fourth Amendment to the United States Constitution.)
In June 2006 Louisiana Governor Kathleen Blanco signed the NRA-backed Act 275, forbidding the confiscation of firearms from lawful citizens during declared emergencies. Similar legislation had already been adopted in nine other states.
On October 4, 2006 President George W. Bush signed into law the NRA-backed Disaster Recovery Personal Protection Act of 2006 (incorporated into the Department of Homeland Security Appropriations bill). This legislation prohibits the confiscation of otherwise legal firearms from law-abiding citizens during states of emergency by any agent of the Federal Government or anyone receiving Federal funds (effectively, any Federal, state, or local governmental entity). Introduced in Congress by Rep. Bobby Jindal and Sen. David Vitter, both of Louisiana, this bill enjoyed broad bipartisan support, passing the House of Representatives with a margin of 322-99 and the Senate by 84-16.