The specmaps are maps that determine how bright, and what colour the reflections are. If they have an alpha channel, that'll determine the envirment map. If there is no alpha channel, the normal specmaps will be used, and if there are no specmaps, the normal map will be loaded as spec.
A ship without spec will look like it is either plastic or molded from glass or something, a ship with it will look like it's metal. All ships have specmaps, but not all have specmaps with alpha. Envirment mapping might look a bit odd, but it is only available in Bob builds anyway, so it won't appear in 3.6. They are included in the installer, in MV-shine.vp (IIRC, I am not all that up-to-date myself).