One way to tell the age of Paul Storie pottery is to research the artist's career timeline and compare the features of the piece you have to known works from different periods. Also, consult with experts or collectors who are familiar with his work.
Another sign is over - monitoring. In many stalker friend stories, you can see that the stalker friend constantly checks your social media, texts you too often, and seems to always know what you are doing. For example, if you post a photo on Instagram and within seconds they comment with details about where you are or what you were thinking when you took the photo. It's a bit scary.