The star marks the spot where the Mk13 single-arm missile launcher used to be mounted. All Perry-class frigates have had these removed, stripping the ships of their zone anti-air capability. The Standard SM-1 missiles were no longer up to the task, but the removal of the launchers also means that the ships lost their capability to fire Harpoon missiles.
Some of the Perrys are going to get 25mm guns mounted on the station. I’m not sure if this has been done yet or not.