Yeah. But the Quran says Abraham called his people Muslims. So saying pre Islamic shows you are not referring to the OP of this thread which is an islamic argument and a Quranic argument. Even though you dont believe Quran has anything to do with God, for the sake of this thread the text has to be taken into account. Its a methodological approach, not a philosophical one if you understand what that means.
Theologically, yes. All prophets always taught Submission to God (Islam), and their true followers were submitters (Muslims). But this is only Theological. However historically, it was Muhamamd who only called religion, Islam and the followers Muslim. So, historians, when they say Islam, they mean specifically Religion of Muhammad.
Anyways, it is correct to say, that according to Historians, Arabs, before Muhammad already believed in Jinns.
Now, how did they know that Jinns exist, when no one has ever seen such a species? And if they saw them how come we, and the people who live now, and specifically scientists has never discovered them? Then it becomes evident that the belief in Jinns was just a Myth, and Muhammad used it as an analogy, or the so called "Mutishabihat", in the Quran.
Anyways, when I say, Jinns are symbolic in the Quran, this is not my own idea. This is what I read in the Writings of Abdulbaha and Shoghi Effendi, who were central Figures of the Bahai Faith.