All products made out of precious metals are legally certified by INCM - Oporto Assay Office.

The application of assay office marks is only mandatory for silver pieces that weigh more than 2 grams and gold pieces that weigh over 0,5 grams.

You can check the table with legal punches here:

When in doubt all consumers are able to check the veracity of each hallmark at INCM.

Gold and Silver daily quotes available here.