I'm guessing in the Assembly Room there is an Instance list that will tell you the names of the objects imported from Wings3D.  I'm curious if the knife is in two pieces, since there are two different shaders.

If the model is in two (or more) pieces, you can click on one piece in the list and edit its shader (change it's Top Shader to Multi Channel) and tell it what color, hightlight, shine, reflection, etc to use.  Then go back to the Assembly Room and click on the next piece and change it's Top Shader to Multi Channel and assign its color, highlight, shine, reflection, etc to a different setting.

Metal has no color, but has lots of highlight, shine, and reflection.  The handle will have very little highlight and shine if made of wood.  And more highlight and shine if made of plastic.  But no reflection for either case.

Post a render of it to show us your progress.

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