By research, I assume you read about this in DiceX's thread. Assuming that the book is original and hasn't been married by anyone but the production line, it's an interesting situation. The presence of extra production staples should not impact the grade. It may or may not receive a note stating "Manufactured with extra staples." However, the extension of the cover may prevent the book from being graded. CGC used to reject and return books with significant "overhang", because slabbing them could result in causing further damage to the cover. I am not sure what they are presently doing.