BTB....Wish I could give you a ballpark idea, but all I can offer is another place you might try. I'm not sure if the gunshows at ExpoMart in Monroeville are over or not... also, Greensburg seems to have gunshows frequently. These places usually always have people there familiar with these items. You may wish to check there, if it is an option. Being in the Apollo area puts you fairly close.
There are a whole bunch of people on there who may be able to give you a quicker idea of value, however. Good luck in your search......