The 1915 4 Ducat is a restrike (1920-1936 mintage 496,501,000) of that type of coin issued from 1872-1914 for that one variety. The 4 ducats cheap drugs online of that period weighed 13.9636 grams with actual gold weight of .4430 oz. Since the coin you have is a restrike it is listed as such, but no other info is provided. It is basically listed in the world coin books so that if a collector finds that date, he will know it is not really part of that series. It does have a value listed as bullion value (BV) which means it is worth the value of Austrian gold coin in it but they fail to tell just how much that is. Hope this helps some.