The easiest way to see if a song has been zedded or not is to go to A-Z by Artist and then click on the artist for that song.
A-Z for Song for particular years can be found below. Just load the page and click on the arrow icons at the top line of the appropriate column. You can sort by artist, song title or guru. Specific A-Z by Song lists are available for songs before September 2017 at the end of the list.