Here are all the parts for the stock and trigger. Pin is fastened as a through tenon into the lever. The trigger is forked, the fork floating in a pair of sockets under the bridle. The limited movement of the pin prevents the lever falling off as the pin binds in its tunnel.

I used one hole for binding on the bow, the other for a rope stirrup, but, I crossed that rope under the edge of the bow and they hold each other in place. The front of the bridle isn't dished or socketed to receive the bow, which is unusual, but the rope and bow work really well together