Is it possible that these detectors were aimed at being ready should Iran develop and use nerve gas against Saddam's regime? Yes ...
Anything is possible. Is it probable? No.
In Saddam world, there is nothing for defensive purposes, it is only for aggression.
Do you believe that Saddam would have waited for the Iranians to ave Chemical Weapons and he does not? He understand very well that Chemical Weapons are what saved his regime in the Iraq-Iran war, and that is why he was always obsessed in having them.