It seems to me that all it was (or at least early versions of it) is an EXE which played the video we know as the FreeSpace Alpha Trailer.
On topic, I've made Diffuse/Specular/Emission maps from this:
The diffuse map was made by subtracting the red from all components of the texture, normalizing it, and a few other tweaks (some done manually).
The specular map (-shine) had a bit too much purple for my liking, so I decreased the saturation in the purple areas. It was based entirely on the diffuse map.
I wasn't sure quite what to do with the blue tint in the emission (-glow) map, or whether or not to make that map brighter (e.g. around twice as bright), but I uploaded it without doing so because this way if you want you can do it.
They're .png files, but PNG uses lossless compression (unlike jpeg/gif), so converting them to .tga or making them into .dds won't be hurt by that.
