Gunn Smithyis right the OPs ? has barely been answered !!
The early GPs up to the mid 90 had a 12# trigger spring & later 10#.
But heres the problem , 1 end pushes on the trigger the other end pushes on the trigger gaurd housing lock latch.
It`s importatnt to get that latch to seat correctly everytime it`s removed from it`s seat .
A word of caution, if ya try to alter fit here & ya get it too loose then use a liter spring wha`ll happen is the trigger guard housing will unseat a bit under recoil, thus affecting DA/S trigger pulls.
I have even seen problems with this with factory spring because the owner put his favorite gun grease on the latch to make it easier to depress.