It seems the patch was distributed under two different names "lfc-sky.zip" that was released without .nfo and .diz files and then "sky-sde.zip" that was released with .nfo and .diz files. It's possible that the "lfc-sky.zip" file is a preservation attempt already and not the original release from 2001. "sky-sde.zip" on the other hand looks like a legit release that Lightforce would have released at that time.