I think it's pretty rare for a series to have actually re-used the same script twice. I cannot recall any LOST IN SPACE re-uses, other than the usual Irwin Allen reuses of sets, costumes, and footage. I don't think he reused a script though.
The closest he came to that was with VOYAGE TO THE BOTTOM OF THE SEA recycling a lot of details from the feature film and redoing it in "The Sky's On Fire". He also ripped off his own movie THE LOST WORLD by recycling footage with David Hedison chasing Vitina Marcus, both of whom starred in both. And then there was the lizard footage that showed up everywhere. But those are not really script recycles - just footage recycles.