An update:
While I was considering these coins and then out of town on a business trip the owner took the coins to a local coin shop that I know. The dealer offered $325 for the $5 indian, $675 for the $10 indian, $750 for the $10 liberty and $1300 for the 1927 $20 Saint. Those offers seemed really generous to me, but the owner strikes me as honest and I don't think any of this is made up. The value really comes down to grading, of course.
I am inclined to match the offers and buy all of them, other than the $20 Saint. Although the Saint is really nice, I could buy a 1927 Saint certified and graded MS63 for less than that if I really wanted one (see Apmex). On the other hand, the offered prices are probably below what I would have to pay retail for the $5 and $10 indians. The $10 liberty is intriguing. It is obviously a bit beat up, but I think it has a decent shot at a XF or even AU grade if I send it in, which would make a big different in value. A bit of a risk, but the $10 liberty could end up being a deal.
Am I way off here? I assume that at worst I am paying a slight discount to retail but have a shot at coming in a much better discount.