A Duchenne smile contracts the zygomatic muscles of the cheek and eye, forming crow's feet. The crow's feet indicate that the smile is genuine and that the smiler is truly happy. It was discovered by and is named after Guillaume Duchenne. (Wikipedia)
Yes, but it takes more concerted effort. One must be aware of this and practice it. Thus making two catagories: the authentic smile, or the polished pr agent. Insofar as the detection, there's an element of subtly-awareness and intuition involved--those in greater touch with this skill do better spotting a contrivance.