The previous label was blue because the book was all original to itself. Wrapping a non-original cover around a coverless is considered "marrying" the cover and is considered qualified by CGC to differentiate between a book having a loose but original cover to that exact book. Most of the time it's fairly easy to see a coverless copy married to a cover as the staple holes rarely line up exactly. Marrying a centerfold can suffer from the same misalignment and CGC would consider THAT qualified too, but from an appearance standpoint, it would be hidden inside the slab, whereas a cover misalignment would be visible thru the slab. Marrying covers or interior pages gets you a green qualified label.