If that is like the Mopar kits I have installed, with the 7 way that you are going to install, there is a 4 way connector that plugs into the factory 4 way connector. You can use the 7 way and when you need the 4 way, just unplug the added 4 way and pulg the trailer into the factory 4 way. Hope that makes sense.. All in all you will not lose the factory 4 way..

 

Parts/Service is right. My truck has the tow package and I have the 4-Flat underneath the bumper and seven way in the bumper.

But, we know parts/service is always right.