That's a real rare badge from what I've been told and was only fitted to a narrow range of 59's. My late 58 also has the 3 color badge but I believe it's incorrect for my 58.
That said, I can't help you with the repair - the enamel is really cloisonne - from wiki:
<span style="font-style: italic"><div class="ubbcode-block"><div class="ubbcode-header">Quote:]Vitreous enamels in the different colors are ground to fine powders in an agate mortar and pestle, then washed to remove the impurities that would discolor the fired enamel. Each color of enamel is prepared this way before it is used and then mixed with a very dilute solution of gum tragacanth. Using fine spatulas, brushes or droppers, the enameler places the fine colored powder into each cloison. The piece is left to dry completely before firing, which is done by putting the article, with its enamel fillings, in a kiln. The enamel in the cloisons will sink down a lot after firing. This process is repeated until all cloisons are filled.[/QUOTE]</span>