IRC (cancelled 7/JUL/1973) with an original value of "1 PESO" surcharged in red "VALOR m$n 12" IN THICK LETTERS, also with additional postage of 90c. San Martin(to make a total of 1.02 Peso ley 18.188, 2c. over the correct rate), very interesting mixed postage and change of value and currency! (Image)