I have no idea if their 'value' is on the mark, but those are definitely worth a good bit. Not many that are actually 'rare'. But the centering on almost every stamp is good. Even for many relatively common older stamps, there is a huge premium (well above catalog value)for very well centered and even more for large margins. Combine that with original gum/never hinged and - ca-ching! Tough to get that price without graded certificates though...