The original strikes, restrikes and plated versions were all made from hand engraved dies. Please note, though, that unlike Plum, Orchid, Bamboo and Chrysanthemum and the Palace Lantern sets, only one side of of the pagodas and goldfish was hand engraved. The other side was etched.
The brass medals may have suffered a higher rate of loss due to the base metal they were made from. The Jianzhen brass set is even fewer than the silver version. There are four known brass sets, including one in the museum of Shanghai Mint. The silver version is extremely rare, too, but not this few.
One side of the 84 silver pagoda & goldfish were hand engraved and the other side was etched. Are these the only two medals struck like this? If so, these two are very unique and rare. Makes sense these two silver medals could rise on the collection priority list.......