The piece I circled in red is what deactivates the firing pin safety, and it is not under any spring tension. Yes earlier models did have a spring that did put this under tension, but it was not near enough to overcome the striker safety block tension. Sig removed this spring just as another layer and to say they did it.
The spring circled in red is the one Sig no longer puts in the 320 fire control. They deleted the spring sometime in 2019. I received an armorer update from them about this, I will see if I can dig it up.
TXPO