Yes they are! Today Soo has made stone 34, which is a dinky wee little thing, and I've made stone 53, which was the first stone discovered to have carvings of axe designs, way back in 1953 by RJC Atkinson, when late afternoon summer sunshine shone obliquely across the face of stone 53, throwing the images into clear relief. And a close examination of the cardboard version under bleak office lighting reveals the same thing! Here I have circled the area containing the tiny axe designs:

The discovery of these axes forms a major new contribution to the field of Cardhenge studies, as it unequivocally dates the formation of the cardboard to the Mediterranean Bronze Age.