I honestly can't tell if something is outlined, and for the most part don't really care.
I do sometimes sense, however, that a writer isn't quite as good at putting together a coherent plot as other writers may be. For example, I read a fantasy trilogy and the first two books seemed tightly plotted but the third was kind of...meh. Meandery. It was still good and had plot but didn't seem as strong as the first two.
Could I say that the writer used an outline for the first two and not for the last? No, because I honestly can't tell. Some people can write well without one, and some people can't write well even with one, so I really can't judge, not without knowing the author's personal abilities.
I can only speak with certainty from PERSONAL experience with my own stories. I fully outlined one novel and it's very stale to me, quite forced. I don't outline most of my other stuff and it just seems to flow better...but it quite possibly meanders somewhat. *shrug* Only another reader could give me an objective opinion on what seems outlined or not, but it would just be their opinion.
In the end I don't much care except that a story is written well.