Remember that within the game, there is also added lighting, and mip-mapping, and anti-aliasing... all of these things are going to make it look like there is a greater range of values than there really is.
Also, how many planes in WW2 were covered in the full spectrum of color?
It really shouldn't be an issue for you... I guarantee that a properly done 8-bit texture will look as good as any 24-bit (or even 32-bit... yikes!) texture.
If you're having problems with colors on your skins, it's probably not a problem with the format, but rather with your technique, or even a limitation of your bitmap editor.