So now that they have the auction items up, I looked and it is the 500 and not the 505. (And they only have 15 available, so a pitiful auction at that).
I double checked my email and it does say and link to the 505. I called and asked, since I have nothing better to do right now, and she said they didn't have enough stock for the 505 in auction and so they changed it. If you look the 505 is out of stock on the rewards site, so that does seem to be the case.
So don't bother. Sorry.