Looks legit. I called the number (specified in the thread waylay00 linked to) and it was indeed Asus Customer Support. I pressed option 3 for RMA dept and spoke with an agent after a 15 minute wait. The agent wanted the serial number of my board, until I told her that everything was running great, but the chipset fan was making noise. She took my info and gave me a reference number for the package. They are sending me another fan! I asked if the fan would be identical to the one its replacing, and she said yes. So I doubt the fan will be anything improved over what has been originally shipping with new boards.
Damn shame, but at least I have a replacement in case I decide to sell or RMA the board. I'm watercooling the chipset now anyhow, the noise and piss-poor temps with the stock cooler made me laugh - for about 2 seconds. Then I yanked that sorry excuse for a heatsink and slapped a Koolance block on that mofo. Oh hellsyeah.