Show us the auction. Or pics or something, I doubt anyone here is gonna bid on it so you don't have to worry.
bout 490 usd difference between that and a new one. now if your going to buy it depends on the last day, how used it looks, what kind of finish is on it and dont forget to ask for lots of photos of any areas that you are suspicious of.
That's pretty much the average price for an SL1 on eBay. It's a bargain if it's brand new with a decent flame or maple top.