Thanks for the responses. I think if someone held a gun to my head, I would go with converting the existing lock to flint. The pan and cock from the Davis Late Ketland might work. However, given that this is a contemporary poor boy rifle, I don't think it is financially reasonable to convert it to flint. I am going to recommend that he sell the rifle and buy a flintlock that suites him. There are plenty for sale and lots of people who would make him one for less than I would estimate it would cost to convert the current rifle to flint.