Hello, Matrix
Unfortunately, what you report shows that the model does not include the wings, so there's nothing anybody can do about it.
Back in the day when Eric Cantu made those great models, people had less powerful computers and many modelers left out the wing views in an effort to minimize the impact on frame rates.
Seem to remember that there was discussion of this on the Historic Jetliners Group forum, with the same conclusion.
By the way, that site has a fine assortment of 737-300 (as well as -400 and -500) repaints, panels, and sounds.