Everything you said, but i would of thought Toht would of pushed the burnt hand into clay or plaster of paris to create the copyI strongly prefer the cleaned-up version that was made. It tells more of a story, and it suits Belloq's sense of precision. I can imagine him taking a tracing of Toht's burned hand, and then refining it and cleaning it up before crafting the finished metal piece. The Third Reich insignia and Belloq's signature on the back really complete the effect. It feels like something he crafted carefully, not just to locate the Ark, but also to be a personal memento that he could keep as a symbol of his victory in later years.
I have a shelf full of Indiana Jones prop replicas, and this piece always gets the most attention. It was never shown in the film, yet people immediately know exactly what it is. If it was just a misshapen lump of metal with a rough inscription, I don't think people would make the connection so quickly. They'd just wonder what the damaged one was for. But as a near-perfect twin of the original, the first words that come to mind are "duplicate" or "forgery", and that quickly leads to people understanding what it represents.