I took a look at my doors and can't see any evidence of staples, but I was sure they were stapled in place. But I don't have a stapler that would penetrate the metal anyway, so will likely use some sort of adhesive to put mine on. They definitely go on the inside of the window, basically to keep the dust out.
[on edit] I think we're looking in the wrong place for the staple holes. They attache to the inside window molding per
this post. I can go look at my inside moldings tomorrow. They're out in the dark right now.
