Have you seen it someplace you can link us to?
By "both sides" do you mean inside and out?
For example: in this one you get the dots along the perimeter of the heart die cut AND the frame left behind. This is called "in/out" dies.
https://wholesalecraftingsupplies.com/products/in-and-out-cut-stud-dot-heart-die-set-gina-marie-designs?_pos=4&_sid=1ca06d66f&_ss=r
There are actual dies for bookmarks...
PTI has this set with a design
https://www.papertreyink.com/pti-dies/papertrey-ink-stitched-bookmark-collection-die/