Cook Islands (Aitutaki)
1981 Royal Wedding, IMPERFORATE Set of 3 MNH

Singles from the top corners of the sheet

On white gummed paper

Scott 247-9, $2.25 for a normal set of 3, Plate Proofs or Imperforate are not listed

Stanley Gibbons Catalogue: #391-3, Plate Proofs or Imperforate are not listed

I believe these to be Plate Proofs. The printer of this stamp issue Fournier S.A sold its philatelic archives of stamp artwork and proofs in 2007 through the German stamp dealer and auction house Gärtner.