This "Datsun 1200" mark goes on the back of the sedans: 84822-H1600 EMBLEM-'DATSUN 1200' TRUNK LID (SEDAN) This is out of stock in the USA. But sometimes they are for sale on eBay (new old stock).
Too Intense Restoration also sells them: Too Intense Restoration. Being rare in USA, the prices are accordingly.
Note that coupes have a non-cursive emblem: 84822-H1856 or 84822-H1806 EMBLEM-'DATSUN 1200' TRUNK LID (COUPE)
Are these still available from Nissan in Portugal or Australia?