CPA here, just make sure you include basis for the asset dispositions on your return. I can’t imagine a situation where anyone will actually owe tax aside from some odd windfall gift of an extremely expensive, and you sell it for a gain.
Are there local resources in the Bay Area? I’m also in PH/Concord area and interested in acquiring a Marauder Pistol. It would be even more enticing if there were a few enthusiasts also in the area.