Are there 1957 silver metal wheat pennies?

There are two ways to have a 1957 silver metal wheat penny : 1) If it was struck on the wrong planchet (like the silver planchet for a dime). This would be considered an error coin and can be worth as much as $50 2) If somebody has silver plated a normal penny. This would be considered a novelty item and would have no added collector value.