I know the UD4 page hasn't been updated in a while. One of the entries is for Nippon-Columbia ST-5001 with the notation "contents unknown, may or may not exist". It does (see attached pictures), but it's not UD-4; instead it's one of the those mixed records, with one side CD-4 and the other is RM. So you can take that one off the UD-4 page.
