Russian vintage stamp date unknown.  A single stamp is divided between the two cufflinks. 

Vintage Stamp Cufflinks are part of the Libby B.K. line inspired by journalist and adventurer, Nellie Bly. In 1889 Nellie Bly circumnavigated the globe in 72 days, beating the fictional character from Jules Verne's Around the World In 80 Days just 16 years after its publication. Each of the pieces in this line are based on the types of objects we imagine Nellie encountered during her travels. 

Set in hand-poured resin. Cast and hand-forged bronze cufflinks. 14K gold plate. Cufflink face measures 7/8th inches by 1 1/8th inches. Each set is made with actual vintage postage stamps. Colors and markings may vary slightly from piece to piece. France set shown for size on male model, Wolfgang A. Taco.