See in some books like the Wybauw one, he molds his slab of ganache in a frame and allows it to cool , then pass a very thin coat of chocolate on one side, cut the slab and dip the squares ( chocolate side down ). Same concept as for the caramel slab. In another book I was reading, the chocolatier actually made a very thin coat of chocolate on a parchment paper and before it solidified completely cut out rounds or ovals or other shapes, then on top of this thin chocolate discs he would pipe his ganache , allow it to harden then dip it with the chocolate side down , so you have the hard part on your dipping tool .
I was contemplating buying truffles shell molds so I can make my own shells to fill.
This is the type of mold I am talking about.