No, the guy in the article was wrong - it's been possible to do in PRMan since at least 2000, but it was very slow (they didn't have any decent acceleration structures for the ray intersection), so it generally wasn't used that much. But it was possible.
For PRMan 13 (which Pixar used for Cars in 2006), they added semi-decent acceleration structures which sped up raytracing a bit. But you still had to use custom shaders to cast rays.
With PRMan 17, ray tracing is now a first-class citizen in PRMan, and it can also trace rays from the camera instead of doing the traditional (pre 17) REYES rasterization of the surface and then shading that surface for reflection based on ray tracing.
