Think of all the rock quarrying that has gone on since humans developed tools.
Now think of someone finding a large dinosaur skeleton of, say, brontosaurus.
How would they explain its presence? Legends...
Now, about the riddle of steel, let me tell you of the age of high adventure!
Perhaps. Given the same premise in isolated cultures absent cross cultural influence, I'd be curious how you would explain the rendering by these cultures of similar creatures, with similar attributes.