Hi, does anyone know what is the market price for a 1980 China Olympic Proof Coin Set? A local coin shop is asking US$3600 Comes with original wooden box by China Mint, on the box it says a limited mintage of 1000 sets, with COA, complete with 2 gold, 4 silver and 8 brass coins, gold and silver look BU, copper has slight toning, shame cannot take photos to share Any opinion?