[amiga386]

No, you need the original mix to remaster it yourself.

If you just amplify the whole track until its max amplitude reaches the medium's maximum, yes you could undo that.

But the loudness war aims to make the whole track even louder than that, by quietening those max peaks so they don't clip, then that gives you room to amplify the rest of the track even further. The dynamic range of the recording is permanently reduced.