Was there anything else the bartender did to receive the thank you? No.
I'm going to assume no, just to get in more questions. :D You assume right.
Did the man thank the bartender for not shooting him? No.
Did the bartender pull the gun out as part of a joke? As a mistake? As a threat? No.
To scare the man? Yes.
Were the police involved? No.
Was the man interested in buying the gun or another gun? No. (But what an interesting idea.)
Was the man dazed and confused? Did the bartender snap the man back to reality by pulling out the gun? No.