I wanted to make the western crossbow prop seem a little more aesthetically realistic. I figured giving it a cocking stirrup would give it a medieval vibe. The purpose of the stirrup is to allow the crossbowman to keep the crossbow in place during cocking with his foot.

ATTENTION: THIS MODIFICATION IS PURELY AESTHETIC. IT DOES NOT FUNCTION WITH THE SAME STRUCTURAL INTEGRITY AS THE REAL THING.

Regardless of what adhesives you use to connect the two pieces, I can not guarantee that the modification will function with the same quality as a real crossbow cocking stirrup (with the non-zero chance that the two pieces separate whilst loading a bolt, I do not wish to be held accountable for any possible accidents/injuries).