I am sorry to disappoint you, these coins were probably bought during a trip to china (or other asian country in the area) , where cheap non-silver forgeries for tourists were sold for $2 a dozen as early as the 70s (until today). They are not much more worth today, as they are still being sold for the same price (they do appear even as sets in pvc-sheets) therefore it might be had to get any money for them at all.