Dan,
I saw that one also on ebay and at first thought it was the same as the one I have, but then saw the difference in the blade attachments and rivets. Maybe the difference between the two is that they came from two different venders, but have the same application? Another guess...
I was planning on selling mine, but I'm not sure if it is a common fan or if it one for a special HP application. In other words, WIW..