Was there something different about the $4500 coin that made it sell so much above price guide. Like rainbow toning?
No, that one was a No population, coin with no sales history that the man behind the curtain felt a need to insert numbers in a guide.
Non-slabbed coins have non-slabbed grades. How do you know those compare to the slabbed grades? Just because a seller puts a grade on doesn't cut it, does it? There you go. In addition, remember, they're market grading, and on what their market research shows for their labels. So there's another thing. There's money in those labels...