You can tell that engineered floors were sanded and sealed before they were installed. Every board on an engineered floor casts a reflection in a slightly different direction. A solid hardwood floor has a continuity of surface and reflection if it is sanded and finished in place, as it should be.
Hmm, interesting, and your reasoning make sense to me , but I think it would take a very expert eye to spot the difference, I certainly cant tell any difference. and even then the difference should only be apparent if the solid floor was laid , then sanded and sealed. I’d guess that most are finished before being laid.
Good view point nonetheless.