If you are dealing with a factory GM radio in your Cavalier it is unlikely that the factory radio will play mp3’s in any form.
There were factory radios that would play mp3’s in 2002, but they were less than common…
Infact of aftermarket CD headunits at that time finding one made 2002 or earlier… well, they were few and far between.
Cd headunits that played mp3’s didn’t actually become
common until 2004.
CD-Decks that play mp3’s are invariably marked on the faceplate.