I'm not sure if it's just a bad picture on silverstrikers.com. I think that site is more as a reference to see the general idea what the strike looks like, and high resolution pictures would take up a heck of a lot of storage space on the server. I have three of them and they are all exactly the same as yours. I don't think it is an error. Below is a pic of one of mine, same shadowed/double back.

If you want to see Alan's auction, click the link below. Same strike.

Dave.
SS - 1029