Drillings are three barrel combination guns and in nice condition sell for $2500to $5500 in really decent shape. however, two barrel combination guns are a lot harder to come by, and I don't know if they are worth more or less than Drillings. You might contact one of the country's largest dealers and try to get a feel for its value. Anyway, at $1000 you might be taking advantage of your friend.
PO Box 580 - Washingtonville, NY 10992
Phone: (845)496-7584 - Fax: (845)496-2469