I quite like some Kiss songs, whether you define them as metal is a bit debatable, a lot of young people would say no.
KISS for the entirety of the 70's were hard, shock, and glam rock. But, well enough into the 80's they dove head first into glam metal. In the 90's they recorded a few really metallic numbers too, like Unholy from 92's Revenge album and Within from 98's Psycho Circus.
I don't think KISS are metal, but who cares what young people would say about it?
For a great portion of their career, no. But like Deep Purple and some others, they without doubt moved into it later on.
For example?