French-Indo China 1 Piastre 1885 (KM#5) weight 27.215gr.
The one I was just offered was 27.155gr.
The coin looked good in hand but had obviously been cleaned at some time. The edge looked fine but (and now comes the puzzler) at one point on the obverse from about 9 o'clock to 11 there looked to be an excess of metal on the edge from maybe 1 to 1.5mm inwards and maybe about 0.10 - 0.20mm thick (these figures are guestimates).
Unfortunately I'm not expert enough on the ding test.
Having read so much on this forum and learned from so many knowledgable members I decided to pass on this one. Now it may have been genuine and the slight fault in production possible but if it was fake them it just shows how good they really are getting.