Yeah I just checked mine. With a season of use they had no wobble. I then undid the 2 back bolts just slightly and the heel piece wobbled. So I would presume that the back two bolts are not fully done up. Simply fix though luckily.
Cant easily post a pic but its the 2 bolts that just the heads show on the sides of the heel track. You will see the heel piece itself has 2 slight recess above the screws.
However be carefull, most people will be strong enough to strip screws, so it may be best to get the shop that mounted them to do it. Its not that its hard but it can take time to learn just how much force to use.