These two unlisted Guyana FDCs were just observed on Ebay. The stamps have Salvation Army overprint. The original issue of the stamps was in July 1985. The overprinted stamps were issued in April 1995 and commemorated the national SA Centenary. This cachet has the Guyana RED Coat of arms – a standard Post office cover that has been seen also on other FDCs from the country. It is unlisted in the SA catalogue, and as it has not been seen before (to my knowledge), it is likely very rare.