South Vietnam, Foundation of the Culture Institute, October 27th, 1967, Michel Nr. SVN 393; A single stamp in a 10D nominal was issued in perforation 13.
Here is the mint stamp
and here the postally used stamp
This stamp was not officially released imperforate, however, a small number of imperforate trial proofs have come to market. Here is one of them.
Enpreuves de Luxe; STCV-Roma-membro del gruppo Thomas de La Rue, Londra inscrobed at bottom right.
Registration Nr. 200740