What were the dates of the law changes that caused the 3 or 4
indications of date made? There were international agreements at 3 or
four key times as to the marking of imported goods like jewely. For
example, and I'm just using dates here that I made up: if there are no
stamps then the item could be made before 1901. If it says: "Germany"
or "France" then it could be made before 1931 and after 1901. If it
says "Made in Germany" or "Made in Mexico"  then it would be made
after 1939. If it has a paper label saying "made in wherever" then it
was made after 1951. Laws were changed at certain dates enabling us to
know that it was mfd between such and such. That's what I would like
to know. Thank you.

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