I've caught a few full episodes while visiting my father (it's one of his favorite shows). My impression was that the interactions between family members (and/or employees) seemed scripted at times (more often than not, actually), but the interactions with customers seemed legit to me, i.e., not scripted, so I'd be surprised to learn that the items sold were actually props and the customers were actually just actors reciting lines in a script. Until shown otherwise, I'm thinking that the items brought in are by real customers seeking to sell their stuff, the experts are actually that, and the prices agreed to are real.
