So yeah, Collecting guns is a thing people of means do in the US for fun when they’re not keeping them around for hunting and dissuading vermin. And skulls can be obtained for a variety of reasons. (I had a set designer with six-plus skulls he’d use as molds for dozens of plaster skulls when he needed them for film settings.)
Unless he’s committed an actual crime, or even just needed a license for collecting guns in his county when he had none, this is essentially reporting a celebrity likes the wrong kind of porn.