I installed 2 Bike Pro wheel chocks in my pu several years ago. These units have a flat plate that is secured to the bed floor and the (removable) chock itself slides into 2 lock downs and secured by tightening down accorn bolts. Never a problem. The Bike Pro has a hinged cup that cradles the back of the wheel and is secured with the weight of the tire on it. I traded tv and removed both Bike Pros to mount one in the new tv and the other in the Mountaineer.
I just ordered a Mountaineer 347 THT and plan on having E-tracks installed as additional security. I was told by the dealership the D-rings are secured to the frame.
Sitting on the edge of my chair until it comes in.:)