Yes. On the sig it lets it down slowly but that's of no matter.
A decocker or manual decocking lever allows the hammer to be dropped on a live cartridge without risk of discharging it, usually by blocking the hammer or retracting or covering the firing pin before releasing the sear. This eliminates the need to pull the trigger or to control the fall of the hammer
Sig firing pin has to be operated by the trigger not the decocker