Are Wanxian and Wanzhou the same place?

Yes. After Chongqing became a municipality directly under the Central Government, Wanxian County was abolished and Wanxian Immigration Development Zone and Wanxian District were established. Wanxian District was renamed Wanzhou District (still under the jurisdiction of Longbao Management Committee, Wuqiao Management Committee, and Tiancheng Management Committee) , Wanxian Immigration Development Zone was renamed Wanzhou Immigration Development Zone (which manages the six counties of Kaixian, Zhongxian, Yunyang, Fengjie, Wushan and Wuxi that have immigration tasks).