Hi Paul I would agree that the piece is not genuine. The details are quite mushy, especially the ear of corn next to head (left of 'H' in 'HAC'), which looks like a blob. Without reading that the coin weight 28G I thought to myself that the shape looks too circular and the width seemed, at least based on picture, a bit thin. I have several (though from Utrecht) and they are a good bit thicker width-wise. Also, you will almost never encounter a type so perfectly circular, the planchets are usually asymmetrical. Regardless, the coin should weigh around 31.5g; 28g is quite too much off.