Thanks Leigh.
I wondered that as well, as the lioness is a more brown color. However, what makes me think the white metal was not ever applied is that the coloring of the lioness is so even and consistent. I would expect if it was tarnished it would be more irregular or probably even have some areas of the white metal showing through.
These aren't great pictures, but I took one of the badge next to another one that is a little grungy, but you can easily see the lioness.
Then I took a close up of the lioness on the badge in question and there is just no evidence of any white metal. In fact in the few slightly worn places, it looks brass.
That's what's making me think it is an unfinished badge, which if that's the case I like having it in my collection as an oddity.
Terry