In my experience with these 'half stock' rifles it seems to be that when the forestock broke during the period of use, it would be trimmed (often capped off) and a metal rib of iron or brass pinned (or even soldered) to the bottom flat of the barrel to carrry the ramrod.
In New England, this situation was sometimes remedied by adding a forestock, perhaps taken from another gun or newly made for the purpose. Otherwise, the repair was the standard wood or metal rip treatment. Many guns, some early, appear to have been made as half stocks. I do not recall seeing a PA rifle with a scabbed on forestock though some must exist.
Photos would be a great help in determining the nature of the pieces you have described.
Dick