IMHO, No. They are transducers and not noisy by nature. They use a simple variable, non-pulsed, voltage output that is not extremely low current, so should be relatively impervious to noise. I have 3 of them on the 6 and none have shielded wire; No issues in 800 hours. Didn't use it on the 10 either and no noise or issues in 250 houirs.
Garmin seems to spec shielded cable EVERYWHERE and I do not believe all of it is necessary, just them being conservative.
Just one man's opinion and Garmin may know something I don't.
Larry