Well it definitely did something but it also smoothshaded it. I'm using the flatshading method in this thread btw. Can you explain to me what inverted normals actually are? I'm green as forget when it comes to modeling.
It completely smooth shaded it because you don't have any smoothing groups set up, but that's fine since you're not gonna be using those (unless you want to keep track of what and which group of faces are smoothed)
An easier method of flat shading is to just select the whole model with Ctrl+A, then press Ctrl+Shift+W to unweld all of the faces, this separates the faces from each other, so if you were to select parts of the model and modify it in some way, it won't drag neighboring faces with it, but once you're done with your model, it shouldn't matter anyway
You can also take advantage of this method if you want to smooth shade parts of the model by using the selection tool set to Face, then selecting the faces of the model you want smoothed, then just press Ctrl+W to weld them together
So as an example, you could unweld the whole model to flatshade it, then select the tube part of the model and weld those faces together, but since this is Milkshape 3D, you might have to use the different viewports to select the exact faces you want
Does this look fixed? (the one on the right specifically)
Looks
normal to me!