italia458
Are you asking if stall strips are used to improve handling by eliminating wing drop? I guess they may have been but I have not experienced it. If you can get the warning and handling you want with one side only why do both?
If your type is one that has an unacceptable tendency to drop a wing at the stall I would think one of a variety of leading edge fixes to improve the breed would come to mind before stall breaker strips.
Since it is clearly impossible to produce wing after wing where both sides are identical the question of whether some stall handling fix/trimming is needed during production test will depend on the degree of variation and the basic characterisics of a given type when it comes to accepting wing profile/rigging variations.
In my experience the types that need trimming at production test are a small minority. But I am over three decades out of date.