On the watch cases, here's how I would look at it.
Assuming it's all 10K something, the very best it could ever be is 1/10, 10K, which is (10/24) x 1/10 = .42 = 4.2% gold. A pound of pure gold right now is worth $1181 x 14.58 = $17,219. 1% Au would be $172/# and 4.2% = $172 x 4.2 = $722/#. He has 790/454 = 1.74#. Therefore, if it is all 1/10 and unworn, it could be worth 722 x 1.74 = $1256. It could never be worth more than that.
Than we start estimating deductions. Sight unseen, I would have to assume it's at least half rolled gold plate. That would cut it down to, say, 2.5%, or $748. Then there's the wear factor, which I would have to assume to be half, and the fact that much of it might be 1/20 and not 1/10 - another 3/8. All in all, I would say a reasonably safe price to pay, and still make a little money, would be .5%, or $86/#, or a total of $150. I would probably first offer the guy $100. If I were face to face with the buyer in his store, he might just take it. If it were 95% worn 1/50 RGP, I could lose money at $100.
It's obvious to me that this lot of material comes from a karat gold buyer. He sure hit a lick. Lots of stupid people out there. The seller says he has more coming. Duh.