Why does my Rock Shox Revelation 426 Not have a Air u Turn Adjutsment Knob?

I recently Purchased a 2008 Intense 5.5 EVP with The Rockshox Revelation 426. However this particular fork is supposed to have a Air u turn knob on top of the left fork leg but it does not. Why? Could this not be a 2008 fork was I sold some oddball fork. Anyone please chime in.