I have never looked at my leader after catching a GT and thought that it had been damaged from their teeth. Maybe I am just lucky?
for whatever reason up here most of our fish seem to be hooked on the outside of the mouth, they rarely inhale it? I've had one recently though and it had roughed it up a bit.
Sounds like tentative and shy "swipes" by GT chasing surface bait imitations - i.e. skittering gars?
I find that particularly true to have such hook-ups if GT are behaving in this way. Usually they only bite if the strike is forced upon them by essentially placing the lure on their nose or immediate vicinity rather than high GT activity when they will smoke a lure from miles away....