Yes there is the tiniest of faint click when you gently make a twisting motion holding the top and bottom.
This is not new to modern glass sandwich iphones. There is a plastic layer between the metal frame and screen for shock absorption; now not only on the screen but back too. There's also adhesive on the edge of the screen for waterproofing that could be creaking a little when you stress it.
It will make a slight noise, this is very normal. It cannot be rigid like a tank, simply physics. But yes if it is more than faint swap it out under 14 days free at the Apple Store very simple. If you have buyer's remorse that's a different topic.