I guess PJ already knew from the begining about the Tiger Tiger group and found out about their identifying feature in s06e05: the three dots. Therefore Smith knew that Kirkland wasn't part of the organisation. Maybe they show it to each other when they meet for the first time or they're having a special way of starting a conversation. I dont know..
But PJ wants everyone to believe that he thinks RJ has this tattoo. Even Lisbon. And thats why I still think he doesn't trust her at all and tries to trick her into believing he's close to finding out who on the list is RJ. I dont know why, but I still believe that Lisbon is somehow involved in this whole RJ-thing. Maybe even RJ herself, but that means that ALL the descriptions we gathered throughout these 6 years were wrong. And that would be very poor writing. I still struggle to believe that one of those 3 has to be RJ. It kind of feels wrong. We learned multiple times throughout this series that we should never trust the "obvious" things.
I also noticed that PJ acted very weird (they way he talked) towards Lisbon and she was kind of strange too. Maybe it was because of the "goodbye" and he really has strong feelings for her or he's tricking her into bevlieving that she's safe and PJ doesnt know shit about her.
Like I said, it kind of feels wrong that one of these 3 men is RJ. Someone here mentioned that RJ could have removed his tattoo easily. That would make sense IF he knows that PJ found out. But that would mean that there's a leak within the CBI-team of Lisbon.