If it's anything like our 2012, and if I recall correctly you should find some screw heads visible by sticking your head into the cabinets on either side. Our TV was screwed directly to a piece of particle board that was beveled on the left and right sides to match the angle of the side cabinets. The whole board/TV assembly was then screwed into place from within the side cabinets. The screws are several inches long, and their aim was sort of hit and miss with the TV mounting board..
In the attached photo I was in the process of building a custom swing-out tv mount, and you can see the tear-outs from the three original screws on either side. These were covered with strip moldings later. The backboard that the swing-out mount is attached to in the photo is not what you'll see when you remove your tv - it is a newly added board to finish the area that shows when the tv is deployed.
