I think that's roughly late sixties / early seventies? I've a Toikka Pikku-Majakka and a Fauna flask with labels like that. I've also seen a tumbler with a production date of 1966-67 with one.
Sometime ago I tried to work out when which Nuutaj√§rvi label types were used - this is what I came up with (additions / corrections / exact datings welcome!!
). I don't know if any of the different types were used concurrently or overlapped.
1953 onwards they usually seem to be printed paper, shaped like the fish logo.
Circa early sixties, clear plastic, where the top follows the shape of the fish, printed 'SUOMI FINLAND' underneath (I've two like this on pieces dated '64).
Late sixties / early seventies, like the one you describe, rectangular with matt silver foil background and sharp corners.
Late 1970s / 1980s rectangular, curved corners, pale blue fish logo, made of either clear or shiny silver plastic.
Additionally Arabia labels were used (info from Lesley Jackson 20th Century Factory Glass) 1971-77 & 1983-87. I've seen a fair number of 70s pieces with Arabia labels.
I suppose that narrows down possible designers?? I've no idea!