Tailgate bedliner for 2017 Ram

I'm looking for a factory tailgate plastic bedliner for my new 2017 Ram 1500. I asked the dealer, and they told me i need to buy a complete bedliner in order to get the tailgate piece. I have a bedmat and hardshell cap. I just want to protect my tailgate.
A part number for the liner would be helpful as well if it is a way for me to order one.
Thanks, Paul