Brian:
One more thought on this. If Toyota actually intended to back-spec in the fashion you believe they did, why would they do it in this fashion? An obscure list in a TSB that on its face says that it applies to 06 and 07 models? And, though they brought up the matter in a TSB that on its face is for 06 and 07 cars only, there's no mention of of the back-spec in all the TSBs for all rest of the cars supposedly back-spec-ed in a TSB that applies to them? Yes, I've run about a dozen, near-random searches on different models in TIS, and gotten zip. If a massive back-spec is what they intended, this is about the most implausible way imaginable to let people know about it.