A major in two universities is generally a part of the dominant major in the province. You can't judge what level a school belongs to according to whether the major you enroll is one or two. It depends on the comprehensive ranking of the school.
The so-called "one copy and two copies" is not a fixed concept. Some schools in a certain province may have two when they arrive in Beijing and Shanghai, but some majors with good enrollment over the years may be placed in a certain province in order to ensure the enrollment of students.
Officially, there is no difference between one book and two books, just a folk saying. And now many colleges and universities have one book and two books for enrollment. There is no difference between one major and two majors in the same school. They are all diplomas uniformly printed by the Ministry of Education, and then stamped with the steel seal of the school name by the school.