I looked into your concern, I found the same item on ebay and many more like it selling for anywhere between 300-600 dollar for an asking price below is a url you can use to see it. They also claim it is a first edition. Thank you for your concerns.
It is possible that it is a first edition, but it is not a first edition first printing. There were 25000 of those and each says first edition on the copyright page under the line stating that it was printed in the US. It could be a second printing, which is not worth as much. If page 447 has S10 printed in the gutter of the book, you probably have a first edition second printing, without it you don't have much. Good luck.