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Who produced this item, and in what period.
Thank you

Michael Olof Barkman, Varberg, Sweden, Q3=1822.

This character Q3 differs from that in the Swedish character table

This is normal?

Year letters varied from town to town so there isn't any standard font for the letters which would have significance like in English hallmarks. For example the letter and the number could have been punched separately far from each other and in different order (like 2 Y), sometimes V and W were used interchangeably, and there are even examples where the letter is punched in mirror image. So basically you can expect to find numerous variations especially with older items.

Thank you for extensive information.