Some years ago, when the BCA show was relevent, an Asian manufacturer had a full display of cues. Someone from Schon scooped up an arm full of selected cues, handed the booth operator a business card and told him to talk to Schon's lawyer if he had any problems with him taking them. I would say Clark feels he has a say about a knockoff of his designs.
I don't see how a product can have copyright protection without a copyright notice - something like a circle with a "c" in the middle and a date. Most manufactured items have have some sort of warning protection notice. I've seen many paintings with a "bug" for example.
Big Al