Welcome to the FTF Community ngls. Please stop by the introduction section and let the guys & gals know a little about you.
Why do you feel you need a plunger spring? Just as a question. Did you lose yours? Or break it somehow? Or shot enough rounds to wear one out?
As long as you buy the size spring for the length of your frame/barrel ( Commander/Officer - 5" vs. 4" or 4.25" ) you should be fine.
I believe you have the 5" Frame.