When the Man in Black wakes up with a noose around his neck, there are only 4 distinct loops in the hangman's knot. A few seconds later, he cuts the rope and collapses to the ground, and there are now 6 distinct loops in the hangman's knot.
Dolores tells William: "They say great beasts once roamed this world, as big as mountains, but all that's left of them is bone and amber." This is a general allusion to dinosaurs, of course; but, more specifically, it's a tip-of-the-hat to "Jurassic Park," by author Michael Crichton, who also wrote the original "Westworld." The theme of most of Crichton's science fiction was human shortsightedness resulting in scientific nightmares. Crichton's "Westworld" and "Jurassic Park" are virtually identical stories about scientific amusement parks running amok.