In this telling of the story, Giles Corey's last words are "more weight." This makes sense because of the way that he is killed. He is killed by being pressed to death. They piled rocks up on his body until he was no longer able to breathe and he suffocated to death. So, at the end, he was still telling them to add more weight to the pile.
This shows us what a strong character Corey had. He remained defiant even until the moment that he died. He was still telling them, in essence, "bring it on, I can take it..."