Sensor on rear of VTR block

[Gandi699]

What sensor is this? Knock sensor.
My XSi engine doesnt have one so will the VTR ecu just run without it and assume default values if any?

http://farm6.static.flickr.com/5031/5857753258_bc2556a839.jpg
http://farm4.static.flickr.com/3058/5857194213_c95cb59161.jpg

[Gandi699]

Anyone know if the XSi 1.6 8v had one of these on its block? I couldnt see on mine to be honest as it was dark outside and I couldnt be arsed getting a torch haha