It sort of doesn't matter if it's legally true, it's an easy out of the question which is the goal. If the other side pushes harder you can simply assert that's your reading of the terms of the contract and you aren't about to risk breaching your contract.
Even better, after stating the above use it as a segue-way into them disclosing the range, e.g. since I'm not a liberty to share, perhaps you can tell me (the salary range | benefits package ).