Originally Posted by upbnsfrrfan
Thanks for the reply and help. Anyway, is that the dark silver part on top of the wing like the ones i see on some 747 models.
Hi Larry...no, it is the light gray-colored "center portion" of the wing between the forward and aft wing spars, from the root/wing-to-fuselage join out to the near-tip...only the leading edges, wing tip and trailing edge control surfaces are bare metal, usually also the spoilers/speed brakes. Although I guess this is what you mean by the "top of the wing".
This is a bit of a generalization, but is fairly constant.
Hope this clears your confusion. I'm sure there are plenty of pictures on Airliners.net you might find that would show you better than I have described.