1) STORY.DAT is correct, because it's this file: http://www.arcadehits.net/mamescore/home.php?show=files which will be displayed in the HISTORY section. It's not absolutely related with the HISCORE.DAT file. You have to put unzipped into the \DATS\ folder.
2) Good idea. Sincerely I don't recall now why it was removed........