If Greece leaves the euro, which Greek euros will be forcefully converted to Drachma?

If they decide to leave the euro, they will have to enact temporary capital controls to prevent a capital flight out of Greek banks. This means a forceful conversion of all euros held in Greek banks into Drachma. After that the Drachma will devaluate strongly against the euro. What will happen to Greek eurocoins and euro banknotes outside of Greece? Will they continue to be normal euros in the eurozone or will they be no longer accepted and become de facto Drachmas, i.e. you can pay with them only in Greece and they have the same value as Drachmas? Please, don�t give me no BS answers like "There are no Greek euro banknotes." Every euro banknote has a national identification code (Y for Greece)