Do you know WHERE the storage unit is? As the current wife of a person who owns a storage unit, I'd bet they have to tell you whether or not there's a unit in his name. I'd call several close to his most recent home. If it's that valuable, he'd keep it in storage rather than dragging ti around with him if he's the unreliable type who has to keep moving.
But basically, unless you cna find it, you'll probably never get it back.