A guy here in Tucson capped two BG's that were beating the crap out of him in his home. The cops questioned him, but even though he had a safe chock full of guns none of those were taken. I think they took the .38 revolver he used in the HD shooting, but he did get it back a couple days later IIRC.
Now a friend of mine in PA got charged with illegal CCW, and they, of course, took the gun (he only had the one). Even though the charges were dropped (illegal search turned up the gun, plus it was in a locked box in a locked glove compartment - it should have been in the trunk), after 5 months he was still waiting to get the pistol back. It's been quite a few months since I last talked to him so I don't know if he's still waiting.
I only have one HD gun, so if it gets confiscated I'll either have to hope they let me keep my .22 rifle, or one of my WWII bolties for home defense, neither of which is an appealing choice (limited effectivness, or unacceptable overpenetration).