Movie ratings labeled "NR" and "UR". Does this difference mean anything?

On Netflix, and perhaps other places, some movies are described as “UR” and others as “NR”. Do both of these just mean not rated or is there some fine distinction?

NR is Not Rated, UR is Unrated; it’s just different ways of saying the MPAA never assigned a rating to that particular cut.

I may be talking out of my ass, and I don’t think there’s any standard controlling when to use UR or NR. However, IME the typical usage is that NR is used when a movie was never submitted for rating (or may have been rejected by the MPAA for a rating for whatever reason), while UR is a recut version of a rated movie that has not been independently rated. So the indie film I made in my basement is NR, while Disney’s The Lion King: Special Hardcore Porn Director’s Cut Edition is UR.

http://www.differencebetween.net/miscellaneous/difference-between-theatrical-and-unrated-versions/

The above link gives a good explanation. Just to clarify, the MPAA ***owns ***their official ratings (G, PG, PG-13, R, NC-17). They are trademarked terms just like the names Coca-Cola™ or Nike™. Infamously they didn’t trademark X because they though it would make things easier (it did until there were enough non-porn ‘adult’ themed films to make NC-17 useful). So NR or UR are just abbreviations, they’re not anything official (yet)…