Is my object looking at the camera?


I’m in trouble with an animation of a desk lamp… I have to understand where it is looking at, to know if it is looking in the camera (I would like to make it shine, if so).
I retrieved the ModelView and calculated manually the product to transform a simple local vector (0,0,0)->(1,0,0) to get its world coordinates… but it points somewhere else… I mean, it follows somehow the movements of my lamp, but not the right way!
Anyone can help?

Thanx in advance,