Yes, it's legal. No, there is not a chance in hell I'm handing my firearm over to anyone other than a LEO who is ordering me to do so under color of law.
He had better have a warrant to seize my gun. They need either a warrant or an exigent situation to seize someones property. You run the risk of running into an anti-gun judge, I suppose, but I'll always make them jump through the proper and legal hoops before handing over my legally carried firearms. I AM required to turn over my pink card, if asked, but that is all I am required to give up.