And – if so – is it a noir because of its visual style? Or because of certain thematic motifs associated with noir as a genre (e.g., a “disturbed woman” protagonist like those in Leave Her to Heaven and The Locket)?
Asking whether noir is a genre or a visual style is like asking whether a photon is a wave or a particle. (Or whether Certs is a candy mint or a breath mint.) For noir, like a photon, the answer depends on the position of the observer.
Noir should not be defined in terms of absolutes. When presented with a particular candidate for the noir canon, we shouldn’t be asking, “Is it noir or not-noir?,” but rather, “How noir is it?”