I have the service manual for an 2004, and while I don't have it in front of me, the information given in the service manual for minimum rotor thickness was incorrect.
I had a serious pulsing in the front brakes once too. Took my front wheel too a friend's who had a micrometer and dial gauge and we checked rotor thickness in about 50 places on each rotor, and used the dial indicator to check for deflection and run-out. Everything checked fine. We couldn't figure it out, and I was getting frustrated. Finally, I said fuke it and just replaced both rotors with two that were barely used that I had bought from a forum member previously that had gone to wave rotors.
Pulsing brakes fixed. So there was something wrong with one, or both, of the rotors, but we couldn't find the problem.
But when checking the rotor thickness, we measured the un-used portion of the rotor, and even that thickness was under what the service manual gave for a minimum thickness. Maybe they fixed that for the later service manuals.
I just looked it up - In my service manual for my 2004, it shows minimum thickness for the front rotors is 4.5mm, or .18 in. Maximum deflection is .1mm, or .004 in for the fronts. But like I said, that minimum thickness is wrong.
Edit: Hmmmmm........ALFJR, you're right. They list the rotor diameter in my service manual as 298mm also -which is incorrect. Where did you get the spec for the 320mm rotors? I can't find the paper I wrote everything down on, but I documented all the thicknesses I actually measured.