What about final season releases that do have their season number mentioned?

Hardcastle and McCormick is like this; on the spine, it says "Season Three," and on the front and back, it's called "The Complete Third and Final Season."

Examples:

The drama Lost is also like this: Its sixth season DVD set has both "The Complete Sixth Season" and a "The Final Season" indicator.

Home Improvement's eighth season has its packaging indicate "The Complete Eighth Season" and a "Final Season" indicator.

The Golden Girls's seventh season DVD had "The Complete Seventh and Final Season" on the packaging.

Smallville's 10th season DVD set had "The Complete Tenth Season" on the spine, yet the front had only "The Final Season".

Five-O #12 is known as "The Twelfth and Final Season" on all sides: front, spine, and back. This is even on the discs.

An example of a DVD of a TV show's final season with no "final season" disclaimer at all (on the front or spine): Friends Season 10.

http://dvd.shawnlyman.com/covers/large/friends___season_10_front_large.jpg

An example of a DVD of a TV show's final season with no "final season" disclaimer at all (on the front or spine): Friends Season 10.

http://dvd.shawnlyman.com/covers/large/friends___season_10_front_large.jpg

And this, IMO, is the way it should be-- no matter which season the final season is, always mention it by the number of the same, instead of just a generic "the final season" (although "the final season" is acceptable if the number of that season is mentioned somewhere on the packaging).