There are 3 colors for the Sony PRS-505
PRS-505SC (Silver Color)
PRS-505RC (Red Color)
PRS-505LC (Dark Blue Color)
The Sony site may have special edition readers but those will either come with a special cover/case or a special skin overlay.
Sony has changed the page turn battery life over the last 1.5 years, but they don't have different batteries.
If you see a PRS-505SC, it is the same reader regardless of store it is purchased from. Maybe a way for that website to internally identify the products.