That's pretty much as official as it gets.
We know Wikipedia is weak in a lot of areas (and school teachers would agree) but one thing they do consistently well is log deaths among notable people in a timely manner as they occur.
For instance, when Ric Ocasek of The Cars died a few weeks back, the Wikipedia entry for Ric was updated with his death just a few minutes after it was publicly announced.
Wikipedia does an excellent job when it comes to documenting deaths of notable people.