when Patrick gathered the last 5 suspects , and said that Red John have the 3 dotted tattoo , it seems to me that its like his old tricks, RJ doesnt have the Tattoo, its a trick  to see which one of the suspects appears relieved or which one didnt look around him.
he did such trick many times before , may be all the guys who have the Tattoo arent Red John which leaves Haffner and Stiles