My first electric guitar was a blue Kay from Williams Music in Worthington, Ohio.  I hacked out my first smoke on the water and crazy train on that guitar. It was traded in on a squire bullet a couple years later.   I had never been able to find reference to model numbers for this guitar, but I eventually found one on ebay in the same cobalt blue.  It sits in a chipboard case in my basement.

I still browse the ebay kay listings and I found the little blue guitars model number.  The KE10.  A google search turned up this cool catalog scan:

They made many variations of this model in the 70s and 80s. some were made in Japan,later ones were made in Korea.

This is a a guitar that was made by Teisco and sold under the Kay brand name,at least the version made in the early 70s was were made by Teisco.