My LO had absolutely no signs of teeth until one just appeared. She did have "teething symptoms," but everything can be misconstrued as a teething symptom, so I wasn't expecting anything. And six months is by no means late, so you still have time.
No worries, all kids develop on their own timeline. My friend's kid got his first at 10 months, he's gonna be a year by the end of the month and only has 4 teeth.
Re: Teeth!