That is an interesting Groat @bacc. From the picture, I see two aspects of the last digit of the date which are curious. First, the knob at the tip of the step seems deformed and displaced downwards so that it contacts the loop. Second, there appears to be a lighter, loop slightly below the main loop. The two aspects may or may not be related. In the case of the latter, I think that this could mean that the 6 was restruck into the die, giving you a 1836/6.
I'll be interested to see what others think.
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-----Ghanaian proverb
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