am I the only one who thinks the price will stay 580-620 until after the auction in order to have a "low" starting price for bidding?
There is no "starting price". Each bidder submits one sealed bid, for 1 to 10 lots of coins, and that is it. The USMS may cancel the auction at their discretion, presumably including if if they get only "joke" bids, but I haven't seen any explicit minimum price in their announcement.
http://www.usmarshals.gov/assets/2014/bitcoins/