Is it possiblie to remove this?:
(or add one to the second pistol?)

Not sure about adding it to the pistol, but I am very sure that you can remove that discharge effect via this weapon's ODF by setting the flash sizes to something very, very small.

yes only delete this lines on your weapon ODF:

MuzzleFlash = "small_muzzle_flash"
FlashColor = "250 70 70 255"
FlashLength = 0.025
FlashLightColor = "255 192 192 175"
FlashLightRadius = "2.0"
FlashLightDuration = "0.25"
Discharge = "small_smoke_effect"

Thank you!