This next part is going to confuse the op, so let's see if I can explain it better.
Around the 2000's I walked into my local sears store, and they had one of these empty black boxes for sale, so I bought it. About a year later give or take they had another of the same box for sale so i bought it. In the meantime, I picked up a third box also empty, and I thought my two boys were very young why not have some fun and fill up those empty toolboxes to give them as a present when they get to high school.
Now something funny happened but I noticed all three of those boxes were made differently, but they all looked similar, just that the manufacturer must have changed the molds/or tweaked the molds just enough to make all three differently. In other words, one had a smooth rounded lip at the handle, another had a more curved drawer shape, and the last one was a squarer shape to it. So, op I could understand your confusion if the boxes looked a little different but yet they all had the same model #'s.
I do that helps you out a little bit, maybe even sears went with a different company to make them? I don't know the answer but that is my best guess.