I suppose it all depends on what program you are using
Yes, and the specific configurations used within the program.
And, it's not noise reduction in this situation.
Call it what you will - in both cases the goal is to attenuate certain frequencies in the recording, whether the attenutation is performed on a specific known frequency of X precision or the frequencies are calculated statistically as in a noise reduction algorithm doesn't really matter, IMO.
You don't notice that missing frequency.
It sounds like from Karl's experience the frequency of this noise is in such a narrow frequency band removing it isn't noticable. You're right on the money, Karl - if your ears like it, go for it!