No, Troi definitely says "he's hiding something" with regards to the Ferengi DaiMon in "The Last Outpost".
Ah, true. So it's a contradiction internal to this episode, as she earlier speaks of an inability to sense the opponents.
Her speculation on a telepathic shield is probably missing the mark, as Quark in "Jem'Hadar" claims such technology still eludes the Ferengi and basically everybody else as well. So perhaps the Tkon outpost was doing the shielding and distorting here? (Although the "distortion" Riker and Troi refer to is apparently in reference to the fact that the Ferengi loom large on the viewer but are below average height in reality...)
As for the value of gold, the Ferengi probably recognize its relativity: primitives not encountered previously might be fooled into thinking it's valuable, even if other sorts of trade partner might not be impressed by mere baubles.