Great week for TV shows: I'm getting The Office and Nip/Tuck this week. My daughter will probably get me Prison Break II for my birthday, coming soon. I'll wait for the price drop before I get 30Rock...
I saw the Target version of The Office so I can confirm that it's on a fifth disc and according to the sticker, it's 23 minutes long. It also includes a reproduction of the shooting script of the season premiere and a different slip case (I can't tell if the regular one is underneath it).
I did pick up both sets today. In addition to the shooting script you mention (nice surprise), the packaging for the set is unique to Target as well. The regular set only has two plastic trays for four discs, and the Target version has another tray for the fifth bonus disc. The Target version doesn't have the slipcase art from the regular version anywhere in the package - the brown bag is the slipcase. Also of note for Office fans, inside the top of the Best Buy box is a (not removable) reproduction of a Schrute Buck. Unfortunately, the letter is printed on cardstock, not on a watermarked paper.
Picked up the Nip/Tuck Season 4 DVD when it came out and literally watched it in a week! Highly recommend- especially w/ Season 5 airing on 10/30- you still have time...