Fifteen of the 20 Quincy police officers put on paid administrative leave for letting their gun permits expire were back on the job Tuesday after renewing their permits, and the other five returned Wednesday, police officials said. One officer was put on leave Friday, after a spot check of permits, while the other officers were placed on leave Monday morning, said Captain John Dougan. Quincy officers are not allowed to work without a gun permit. Dougan noted that the department had previously said incorrectly that 21 officers were put on leave.