The nn offer first appears on the revenge proof. It featured the name "revenge" in the offer.
This was then changed to return on release, in line with the film name change, and was the offer on the Kenner 48 back. Mine is the palitoy version of the offer, which was a simple printed sticker over the us address in either black or white. This is essentially a Kenner with a sticker.
The toltoys version was completely different. As Carl states, it has the alt address, but what makes it far more unique, is a nn offer on a 65 back card. This is totally unique to toltoys. There is also another interesting point to consider. As the Kenner nn offer was originally on the 48 back card, of which no Jedi release figure debuted (as all of the 48 figures on the 48 back debuted on esb or Star Wars cards). Because of this, it means that you can get the nn offer on Jedi debut cards, such as my erg cardback pictured below, and also including nn himself. This is a very rare and cool card. A lot of the toltoys Jedi cards are going for mental money at the moment.