I am not 100% sure of the exact facts and time spans , but - before Portugal joined the European Union they set aside a period for citizens of their territories to apply for full portugese passports.
After this period you could still get a Portuguese passport as long as the grandparents were
born in Portugal. This is fact because me nephew in Brazil has needed the birth certificates etc; of his grandmother and grandfather.
You can of course double check at the Portuguese Consulate.
boa sorte.
