I bought a 10 oz Australian Kookaburra silver bullion coin, year 1992. I measured the tickness of the coin and I found a value less than the indicated value of 8,7 mm. The diameter and the weight seem ok. Moreover the edge of the coin is not all reeded, but only four parts of the edge are reeded, that is the edge is partly reeded and partly smooth. I wonder If the coin is fake or not, could someone help me please? thank you!