Ordered aftermarket side bars and when I started to install there were rib nuts already installed in the small holes. These bars came with different mounting
That require the hole to be open. A flat bar approx 3" long with a threaded stud on one end and a not welded on other end. Two questions
1. We're these rib nuts factory installed or did the dealer mess with
This truck. My son 'a 2014 did not have the riv nuts
2. Could I modify the after market
By using the part mentioned above for the top mounting
Stud and drill another hole in the bracket and use two 8m bolts in the brackets.

 

They might have messed with your truck. My 2014 came with factory step bars that are mounted in drilled and threaded holes that are on the truck from the factory. I did not like the look although they were different looking being all black but I still removed them. Took about five minutes to remove both sides and would take just as long to mount them.