There are some games out there that had a "Property of NMI Sticker" on the front or on the back. On the N64, there is only one variant of the sticker as far as known, which is a white label and says "Property of NMI" and an address following below. These ARE legitimate stickers, but they really don't count as kiosk games since they aren't ever known to have been played in actual kiosk.* They are an extra little goodie that collectors can go after for their collection since they are obscure.
*Needs more information to verify.
Here are some known examples.