He never asked Numair what he saw in the charms. He knew the mage could see magic - could see it all too easily, to the point that Thom wondered sometimes how he managed to walk around the palace without going flash-blind. Thom knew how many magical artifacts were kept in Legann.
Thom never asked, because he was never sure he wanted to know the answer. He'd had one dream ripped away from him already, and so he'd stubbornly keep at his charms and runes and paints, and if they were mere shadows with no substance, well, he didn't really care as long as they gave him purpose.
So Thom never asked Numair if there was any actual magic to his lucks, but Numair believed in them anyway, and that was good enough for him.