I think however you can assume that someone somewhere had to think of that spelling or the name wouldnt exist at all, why not in 1985. not everything has its origins lost in the mists of time.
Anyway as i said i have no idea whether its true or not i just thought the story was interesting and had a certain verisimilitude worth discussing.
I went back and had a little look on the originating website and they have found a Kayleigh
who is 21, but she changed her name so it probably doesnt count. Could name changing be an explaination of the 2 references you found? who can say (not me anyway)