I think so.  To prevent the ringtones app from showing up as one of the choices in the menu, you might want to put some custom property in and then add a filter to make sure that property is not specified.  Doesn't the music app now share song name and artist? Can we add that here, too.  I don't know that any receipient other than this app cares, but if we've got the data.  For built-in ringtones the artist would presumably be "FirefoxOS Ringtones" or something.  Not really a priority, I suppose.