I'm Just a Guy is a sick tune Alton Ellis cut in 1967-68 ,first solo and then as a duet with Phyllis Dilon.This is the first use of this riddim that is also known as I'm Just a Guy because of this.

But it actually took its name from a Sugar Minott track from 1976-77 that was a hit.There is also an earlier I-Roy deejaying tue. Versions of the riddim never stopped till then.
Vanity Riddim

 

Tunes on Vanity riddim