The only valid test: Record both versions (make sure that there are no time-variant parameters involved, like Humanisation, RoomTone, or Chorus FX etc. ....), make sure that they share the same starting point, flip Polarity (a.k.a. "Phase") on one of them, and play both at the same level. If there's something audible, the files were in fact different. Identical files will cancel out completely.
/Dietz - Vienna Symphonic Library