I am not sure whether these playing card bookmarks were included in decks or were used solely as promotional tools outside of decks. I am also not sure of the age of this card bookmark but going on the image, my guess is it was released in the 1960s or 1970s.
Congress Playing Cards were first produced by the Russell & Morgan Company in 1881 as the finest and most expensive of their brands. In 1891 Russell, Morgan, & Co. changed its name to the United States Printing Company and in 1894 to the United States Playing Card Company. Most Congress Playing Cards came with colourful backs and gold edges (like my one) and were renowned for their unique "Cel-U-Tone" finish (soil and smudge resistant) and for their lavish packaging; two decks were contained in a velour-lined box with a pull-out tray for ease of use.
Congress Playing Cards are no longer produced, having been discontinued in the mid 2000s.