hello
i have to install a new knock sensor. haynes says that it comes pre-coated in sealant, but i don't see any sealant on it.

 

It shouldn't need sealant, it screws into a blind hole. There might be a thread locker to prevent it from backing out, but that would be it. Check the old unit for any thread locker.
Biggest concern would be correct torque valve for the sensor.