Hi sambobnz! Unfortunately, it's impossible to tell from those pictures. There are a lot of hacked players out there. I have a hacked 4GB that turned out to be a 1GB, but I also have a genuine 4GB player. Aside from the color, they are identical.
It's hard to say whether yours will be hacked or not. I suggest you format it as soon as you get it and if it's not 4GB, get in contact with the seller immediately.
Since you said you're getting it second hand, I'm going to assume that the seller isn't in the business of selling mp4 players. That should cut down your chances of getting a hacked one if the guy is just selling his personal player.
Sorry I'm not anymore help. Good luck and let us know how it turns out.