Believe it, they will try anything. In this case, if they try to take you to court, the judge will get a laugh out of it for that day at least. It's so standard, what you and the insurance company did, that I'm surprised the dealer said anything at all after he got the TT.
Why would you give him your TT AND a check for $6700, in exchange for his check for only $2500 ... that's even toooooooo bizarre not to fall down laughing.
You did and got exactly what should have happened - that dealer is now trying to pull a fast one on you. I can't imagine (well, I can) why the dealer would event think you would give him the TT for $2500 and then PAY for the repairs to make it worth $9000 to HIM. That's even hard to swallow for a dealer to think it. He's nuts.