Is this a trick question?
I guess it depends on how detailed you want to get. But yeah, pretty much. Technically, a mirror is usually a sheet of clear glass sandwiched with a backing layer of very reflective/metallic foil (or whatever), so you can reproduce that if you want. But a lot of reflection should do the trick otherwise.
But keep in mind 99% of the effect of reflection is not in the shader, it’s in providing something to reflect in the mirror. If there’s nothing to reflect, nobody believes it a mirror.