Doesn't the track channel meter automatically show the level of any incoming audio signal once record is activated? This would be the pre fade level on a regular mixing desk. As far as audio already present on a track, there is no 'pre fade' level as there is no incoming signal. The 'pre fade' level would be when the output fader is set to 0db, the original level of the recorded clip.
Others may have a better idea of course:)