YES! You are absolutely correct, Breeders are looking to sell off their 2012 hatchlings because it is a big time breeding season kicking in. For a low white Pied that 650 range seems about right, especially for a male.
Another key thing to remember too...is if you REALLY want to get a good deal on a snake. BRING CASH Nothing is more glorious to a breeder looking to sell to see green. Just to be able to physically see it and hold it (one of the reasons why we like to go to expos to buy our reptiles) in their hands makes them a bit easier to weasel down the tag. Like car buying...you don't settle for the sticker price...and Expos are kinda like car dealerships, NOT Carmax!
Another key tip too, is if you buy in the first day of the expo, you wont be able to try for the "closing sale" A lot of breeders by the time the expo is wrapping up, want to move their product...which means less for them to have to pack up and unpack when they get home. After noon of the second day of the expo, you are more likely to get more "bargaining ground", especially if the business has been slow for the breeders at the expo...sometimes people just come to look and buy the cheaper stuff, and basically anything over the cost of a single dom morph or a normal het _____ are the only things moving. If you come around wanting to buy a high dollar snake in the upper hundreds and over 1000, youre much more likely to negotiate maybe another 10% off the "low end" price of the snake.
So if a low white male pied is 650...you might be able to negotiate 575 for it with hopes of settling for 600.