In order to save time, some people consider putting sprinkles or sugar into the candy molds, then pouring the chocolate into the mold. Sprinkles end up on top; work saved, right?
Well not really. The sprinkles or sugar will very likely get absorbed into the body of the candy. I did experiment with the process to give you an idea of what would happen.
Here is the mold I used with pearls, sugar, and heart quins already inside.

And after pouring in the candy and letting it harden, here’s the result:

As you can see, the result isn’t that great. Interesting, but not great.
So…
If you feel that you have to put sprinkles on top of a molded candy, think about brushing a thin layer of the same colored chocolate on the area where you want the sprinkles to be – if you want the candy to maintain one color. If you want, or need, to use a different colored chocolate, just make an attractive drizzle and drop the sprinkles right on top.
Enjoy!