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I have the Norwegian book "Stempler 'Gull-og Sølvarbeider" to help me identify marks on Norwegian silver jewelry. I have 2 questions for anyone familiar with this book;
1) Next to each mark there are 2 columns. What does the number in the 1st column represent?
2)The 2nd column looks like to be date the mark was used. Or is it the date the company began to use the mark?
Thanks to anyone that can help me.

The first number is the registrationnumber in the "Styret for det industrielle rettsvern" - the public authority.'
The second is the date when it was registrated.

Thank you, Tosten.