Ruined pistol silencer will not agro zombies.
Playing on stable, 1PP private hive on the date of report. Had damaged silencer attached to Glock. Silencer eventually was ruined and sounded audibly louder to myself. When the pistol was shot, nearby zombies were not aggro'd. Removed silencer, fired again and zombies aggro'd as expected. Silencer could not be re-attached to pistol. No other players around to confirm/deny if shots sounded silenced to players other than myself.
It is unkown the quality of ammo inside the magazine, pistol and mag were pristine.