Williams is a Snap-On brand. Snap-On outsourced tool box manufacturing to sub contractors who then simply pasted on the brand emblems. A lot of times, you'll see identical boxes and tools with the only difference being the name stamped on the item. Sometimes there are minor finish differences, etc.
Bluepoint and CDI are other Snap-On brands. We have experts here on the site who can provide you much more information than I have.
You have a great box. If you decide to restore it, you'll discover that the decal is no longer available. I had a local sign shop make me a set of identical factory Williams decals using the originals. They kept the template under my account so they can make more. I will gladly pass that info to you in a PM should you want it. The decals cost around 6 bucks.