I just finished an inspection where the floors appeared to be solid hardwood but there was no real way (that I know of) to tell. For the life of me I couldn't find a floor register or any other area to look at the edge of the boards.
I hate to say it is solid hardwood when it may be engineered hardwood, and for that matter, some laminates these days are really good. I did notice that some of the strips (at thresholds mostly) had been face nailed with finishing nails and patched over with a tiny speck of matching putty. Is that some kind of clue?
Is there any way to tell by looking at the surface?