Asked whether the person involved had threatened anyone in the vicinity, the spokeswoman said: "No indication they were being threatening - just that they were noticed by others to have it in their possession."
Police were called there about 2.45am in the early hours of last Sunday after shots were fired into the foyer ceiling.
Police said a "brief altercation" broke out among a group of people outside the bar before someone pulled out a gun. They had earlier been removed from Dr Rudi's.