The art of correctly identifying and assigning pedigree designations is a fine art and CGC is one of the best at doing so. And yet even the best sometimes err. What's a bit surprising is that despite the fact that the Green River Pedigree is one of the easiest collections to identify properly - thanks to the ubiquitous date stamp on the vast majority of the books - and also due in part to this site which now contains nearly 400 scans of verified Green River books - CGC has on three different occasions within the last year - erroneously assigned to or withheld pedigree designations from the wrong books.
The examples shown here are not presented to embarrass CGC, but simply to provide the interested collector with a caution: No entity is perfect. Just because the label on a third-party graded book states certain information, the wise collector is better off adding his own experience and a touch of skepticism. The label is usually right, but far from always.