Don't know which 'book value' you are referring to Marc ... but here is an excerpt from my published catalog on Atlantic City casino chips:

"For users of this value guide, it would be helpful to keep in mind that the following information has been compiled from various sources and represents what the author feels is a fair representation of estimated retail prices from established dealers for chips and tokens in excellent (near-mint) condition.

Many sellers of casino chips use various Price Guides as documented reference sources to price their material. A well-circulated chip is often cited as having a similar value as those estimates on these pages for high grade material. While I personally object to grading systems, there is no question that lesser quality chips, which are worn, will sell for significantly less money than specimens in top condition."