I'm hoping Joss puts two and two together but I also have to wonder if Joss is aware of the significance of the perfume.
When the gaslighting began, Carly only shared her fears with Jason, she didn't even tell Sonny about the incidents until she had to. Dante initially investigated the phone booth incident but that was the end until her arrest. I don't remember Joss being in court every day, only when she had to testify. I could be wrong. When Nelle fell, she was so angry at Carly that she immediately turned her back on her Mom.
Does she even know about the perfume scent at Morgan's grave?