I do believe that Allagans referred to primals as Eikons, and that's why the Garlean Empire calls primals Eikons. I also remember somewhere that Eikons are considered 'lowly' 'primals'.
Isn't Bahamut called an Elder Primal, though? Not sure if this title was given by the Allagans, however. This looks like a job for Anonymoose!