Certainly all restoration should be done on the original before any other processing. Note that there are also harmonics of the 60Hz hum at 120, 180 and 300Hz. The correct noise reduction parameters may depend on what the aural content of the rest of the audio is, which may not be obvious from the few seconds that you have posted. There is generally no point in removing absolutely all the noise if it is masked by frequencies in the actual audio, as over doing noise reduction can produce extra unwanted artefacts and can also sound unnatural.
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