Based on the decal, that is likely a wartime box. It was hard to tell from the pictures but it looks like a leather handle. On every one of those I’ve run across, the rings are split and the handle can be removed by spreading the rings open with some snap ring pliers. There is no need to replace the rivets. To install the replacement handle the rings can be squeezed closed with a pair of Channellocks. I am on the constant lookout at estate sales for old suitcases or valises with leather handles that can be reused on toolboxes and I’ve found quite a few.
-Don