If it has a drop front like it kinda looks in the second picture, the drop front looks to be a waterloo. That box may be a waterloo job site box which are pretty heavy built chest for its size. It is not SO, but it still may be worth buying.
If it's close to you, go take a look and find the Snap-On part number stamp in the back of the box. If it's not there, you can get an even better deal on that box.