I was able to enlighten my friends about the 120 chassis family of vehicles. Are there any shared with the N. American models of LC, Highlander, Sequoria or Tundra?
The 2010 4 runner has no identifiable differences between the frames of it's predecessor. I've been underneath both of them comparing them.
Visual inspection will be tough. The frame may look the same, but the steel thickness may be a few mm different or there may be additional internal stiffening plates in the boxed frame. I sure hope that Toyota has learned its lesson with the FJ Cruiser and has made the 2010 frame a bit stronger or tougher.