For what its worth, I thought the same thing about the intake, but it was brand new clean inside, with 120k miles, but I cleaned it anyway. I guess theres really nothing that goes through the intake (like carbon etc) as long as your filter is good.
You might, just for kicks, spent 10 bucks & do the full seafoam treatment(vaccume tube, oil, gas tank), if your TB / intake was that dirty.
Let me dig up that link...
Edit: thanks to POS... BAM!