No, you faggot. It's the Flehmen response. Some mammals do it when they smell pheromones or other interesting scents. "The behaviour facilitates the transfer of pheromones and other scents into the vomeronasal organ located above the roof of the mouth via a duct which exits just behind the front teeth of the animal." The organ is used to detect pheromones. This organ is responsible for the effects of catnip on a cat. Different breeds of cat make different expressions during the response. Usually they just look like they are panting like a dog.
Cat's aren't robots. They don't need to register scents.