Not necessarily. It would work only if the artwork is embedded in the file itself, not if the artwork was downloaded from iTMS using "Get Album Artwork" command.
To check whether the artwork is downloaded or embedded, right-click the track and look for "Clear Downloaded Artwork" menu item. If this command is visible, artwork is not embedded. In that case you can bring up artwork window (either in Get Info > Artwork tab or the small artwork viewer in the bottom left corner), copy and paste back.