Lan Wangji doesn't know the answer to that question -- he thinks not, but how could he be certain? So he doesn't answer it. He takes his arm back from around Magnus, but only so that he can pluck his qiankun pouch from his waist, pull it open by the strings, and slip his hand inside. The locket is near the top still, just past the note from Claudius that is still pinned to the mouth of the bag, and easy to identify by its texture. He presses it into Magnus' palm.