Can Nanning Gui Jun know which line to take in advance?

You can't. According to official website of Gui Jun Motor Vehicle Driver Service Co., Ltd., Gui Jun examination room is the most experienced examination room in Nanning. As long as he swipes his ID card and enters the queuing area, he can know the route he has taken, and will not inform the examination route in advance. Nanning, the capital of Guangxi Zhuang Autonomous Region and a prefecture-level city, is located in the south of central Guangxi and faces Southeast Asia.