The knock sensor ground is not contacting the bolt

[danieltovar]

Well i was going to install the knock sensor and saw the red wire connected inside the sensor, and the shield wire is not connected to the sensor inside the black plastic. On the pigtail side there is two wires and i saw the red and the black connected to the shield wire so that means that the shield should make contact to the sensor inside the plastic bolt sensor.
So i will cut off some of the plastic and connect the shield wire to the metal part of the bolt sensor? Or leave it like it is thats the way it should be?
Help please want to know if its ok to have the shield ground not connected to anything just to the pigtail only