Product review (5 stars): Consider it cheap insurance to replace this bolt.
Definitely worth replacing, even if the original bolt is in perfect shape and the agitator kit comes with a replacement washer.

This OEM replacement bolt has that blue threadlock or RTV on the threads, which ensures that the bolt won't vibrate loose with time and possibly ruin the motor. And what possibly vibrates more in normal use than a washing machine?

Note: I also bought this because I'm not sure whether blue Loctite (medium strength) is the correct thing to use on the threads because it may to too strong and make it difficult to remove the next time. And blue RTV may be too messy or not strong enough.