I recently popped off the end cap on my 325 and took a look inside. Nothing. The description of the racket from TF's website says:
"Integration of silicon in the lay up of the handle in order to limit the bad vibrations linked to the frequent use of polyester strings (> More comfort)."
I'm not exactly sure if that's saying there should be silicon in the handle, but a websearch indicates there should be. Thinking about putting a little silicon in there myself, after reading the thread about it, wondering if anyone has any input.