Rick2525 said:

... the Bobby McFerrin song is now truncated by two lines worth of "blah" in the end credits ...

Thanks, I was going to mention that. I originally thought the song was truncated. After a closer listen through the previous YouTube links, it confirms that the last "blah" stanza was actually seamlessly excised to shorten the song, which otherwise ends normally. Too bad. The final ... bl-l-l-l-lah! bl-l-l-l-lah! ... was the kicker. :D

Finding 2003+ editions is allot easier than was hunting for the 1989 original-version ones. This first finds Knick Knack it in the supporting role of Extras ..

Finding Nemo Collector's Edition DVD Finding Nemo Collector's Edition Blu-ray

But fear not, Knick Knack takes center stage (with other Pixar shorts) under Pixar's own banner ..

Pixar Short Films Collection Vol.1 DVD Pixar Short Films Collection Vol.1 Blu-ray

BTW, you may have noticed YouTube not having 1080p as a viewing option anymore. That is, not for everybody. Why? Well ..

googlesystem said [October 26, 2013]:

YouTube Drops Support for 1080p Streams in the Regular HTML5 Player

"YouTube switched to adaptive streams in the Flash player and now does the same thing for the HTML5 player, but this requires Media Source Extensions. The adaptive DASH player uses separate chunked streams for audio and video ... YouTube removed the non-DASH streams for 480p and 1080p. This means that you'll no longer be able to watch 1080p videos in YouTube's HTML5 player if you use Firefox or Safari."

But there seems to be a working solution for Firefox in an available plug-in ..

Complete YouTube Saver 5.5.1 (or whatever version by the time you read this)
https://addons.mozilla.org/en-Us/firefox/addon/complete-youtube-saver/

"Download YouTube videos in various formats including 480p/1080p (DASH formats). Convert audio track from videos to MP3 or WAV, or save audio track in native format (Ogg Vorbis, AAC/M4A, MP3). Save YouTube page, video, and comments pages to one folder."