Sterling Dinner Knives

How much is a Gorham Rose Tiara Sterling Silver Set (circa 1964) Worth?
I HAVE A SERVICE FOR 10 (APPROXIMATELY 50 PIECES) OF Gorham Sterling SILVERWARE ESTATE SET; Dinner Fork, Salad Fork, Soup Spoon, TEASPOON AND SMALL Butter Knives. THE ADDITIONAL UTENSILS ARE STERLING SILVER ALSO AND POSSIBLY GORHAM BUT ARE NOT A PERFECT MATCH THE ROSE TIARA SET.
IN THE ORIGINAL GORHAM STERLING MARK ON THE VELVET BOX CASE.
I AM SELLING THIS ON CRAIGSLIST BUT DON’T KNOW HOW MUCH IT IS WORTH. ANY IDEAS?
the year was 1963
if it was used go half of the new set
http://www.silversuperstore.com/gorham/rose-tiara.html