They do?
The original plans showed minor rotation (maybe 15 degrees) but I don't know if it was ever implemented. The way they rotate now is via a slot in the track that engages the cars. I don't recall seeing any slots anywhere but at the top.
These plan are what I was going off of too. Reffering specifically to the SOPs `87 SG, the 53 to 80 ft level has a slight rotation towards the wall right of the cave scene, about 20 degrees to the greek temple and roman road, and about 10 degrees towards the phonetian merchants.
80 to 115 ft has a slight bias towards the abbey, and also to the left approaching Michaelangelo.
115 to 52 just has the 180 degree spin which begins about 15ft inside 180 top and completes as you enter the straight track portion to begin the return to earth.
