Where can I buy the shift knob from the premier trim package?

What is different about it? I thought all GT's had the silver knob, and the V6s had the black one. I have the Premium and I didn't know my shifter or bezel were any different.
 
The shifter knob itself is enirely polished aluminum. The bezel has a ring itelf is the same way. The Premier trim package gives you this, does the pedals as well in addition to adding leather wrapped dash, door inserts and center console. The premium shift knob is black and silver and the base model is all black if I'm not mistaken.