[dfc]

It's the story of a boy named Harold and his namesake crayon

I don't remember the story by heart but I don't think the crayon was named Harold. But I never obsessed over the story so I could be wrong. Was the crayon named harold?

[nsmartt]

This seems to be a mistake. I'm pretty sure the namesake mentioned is in reference to the book title, not the boy's name.

[dfc]

Correct, it is an incorrect use of the word namesake. But I'm not sure what the author's intention was when he used it.