Knock sensor part numbers

Doing the oh so fun knock sensor replacement job. Got the suckers out, and attempting to figure out how to identify a new set. The only part numbers on the sensors are 71 021 M

I've already purchased the new KS harness and all the needed gaskets.

I'm assuming the M is for Matsushita but cant figure out what the other numbers mean. Engine is a JDM replacement that has ran great for 3 years, but no idea of the actual year of the motor. Also no idea if the sensors I pulled out are factory Toyota OEM.

If anyone can translate that part number please post up, thanks!

 

Unless you're sure they're bad, I wouldn't replace them. Replacing the harness is a good idea though. OEM sensors are north of $150 each.

 

No idea of they are bad. It could be the harness or the sensors or both. But to do this job and button it back up with the same sensors definitely sounds like a waste haha