devildodge, I now have a 2019 1500 crew cab, Laramie, Sport. The fold out floor in my 2015 raised the rear floor height by a few inches. This let my dog see out the front window by looking over the console. She could also get her head above the rear doors to see out the windows. Today was her first ride in the new truck and she whined a lot, not being able to see outside. I know, first world problems. I was just hoping that, even though the floor lost the middle hump, I could still get the foldout and have it fit the 2019 floor. I'm thinking I'll have to fabricate something.
One other thing: The fold out floor left some convenient space underneath for smaller, short and long things. It was easy to retrieve those items even with the back area stuffed to the gills.