Yes, the drawer sits on a set of bearing at rest. When you open them and the drawer becomes a lever effectively, the back of the drawer then pushes up onto the higher rollers. But in truth they are fairly tightly set - there isn't really any slop in there. As you say, to keep the drawers in trim, there are also thrust rollers along the side. Honestly though Andy, I am not sure they ever touch that much. Everything else if a snuggish fit in there and there's little room for any movement as far as I can feel.
Chris
Chris