Firstly a few people are throwing around the Ellis mars theory. While it is a good one, Jane never actually shakes
hands with him, therefore it cannot be him.
Secondly is we are to believe Kirkland is RJ ( possibly ) an episode outline saying he is asking Jane about RJ does not mean that he isn't. Because he along with Homeland and the FBI are investigating the RJ case he has every right to ask Jane what he knows. Also if Loriali was killed then RJ knows Jane is getting closer to him. So Kirkland may very wel be asking him to see how much he knows and what lose ends need to be cut.
Also IMDB has put up that there is a season 6. meaning that Kirkland is more likely an associate of RJ and not in fact RJ himself. In my opinion it is impossible to tell who RJ is because even if Jane has met him, we might not have. sidenote.. the flashback episode was there for a reason.. Jane shakes 3 peoples hands... the Judge who asks Jane if he has kids then says, if you want to hurt a man kill his family, second person is virgil the 3rd is Lisbon. I think the shaking hands thing has more to it. Because RJ would have loved shaking Janes hand. For him it would have been pure ecstasy for him. It cannot be Jane, on the fact that he would never kill Loriali.