Question to the united states postal service what are golden replicas of united states stamps on gleaming 22k

they are sealed not used in envelops on the back of these envelops this is stated.: trademarks and copyrights used herein are properties of the united states postal service and are used ubder license MBI,Inc. all rights reserved. cover designpostal commemorative society. i have 8 gold stamps sealed w ith a regular stamp on the envelop statinf first day of issue july 2003. they are 37 cent stamps one is arctic tundra gray wolf,gyrfalcon,caribou,and one is a 3 cent stamp joseph pulitzer april10 1947-new york,new york.and more