Check out the images at this THR link:
https://www.thehighroad.org/index.php?threads/toy-cannon-mould.907120/#post-12329643
https://www.thehighroad.org/index.php?threads/toy-cannon-mould.907120/#post-12329643
Overall this looks like a cannon casting pattern. Can’t tell if I am looking at an I beam or two pieces of matched channel iron with 1/2 a cannon pattern on each channel. The 4 holes in the iron piece is for locator pins to keep it properly alligned. Cannons have to be cast in the vertical format to avoid shrinkage issues along the surface of the cannon.