The only way I know to get shiny gold is luster dust, you could try coloring the chocolate yellow and then dust with the gold. I have dusted chocolate and even painted chocolate with lusterdust and vodka.
I read on here where someone used gold dust, vodka or clear vanilla flavoring with a little piping gel added. Not sure if this would work on top of cake bites because you wouldn't be able to stack them as the deco on top more than likely would not dry. If you could put them in some candy cup liners and not stack them, this may work... just a thought