I thought the original pilot aired in syndication?
IIRC, one actor's voice was dubbed in the original aired version, and there were several shots of background aliens deleted in the second version. The music might have been different as well.
It would be nice to have the original if only to compare the differences, much like Star Trek fans have the unaired "The Cage" pilot, and the version incorporated into "The Menagerie" two part episode.