The first chip has a sticker on the front and was used as one the front of the rack chips that were seen in a closeup shot when they wheel the chip carts in to the replica vault. All the chips behind the front ones didn't have stickers (second chip). The third chip has been speckle airbrushed by the production team to simulate burned or scorched chips that were used in the post vault-explosion scene where there are chips and debris scattered around the floor.
