Shrapnel,
My observation was meant to be a 'heads-up' - not a criticism.

I have collected Powell guns for over 20-years and have a significant collection. My
collecting focus is the 'lifter' (guns like yours) so I have a firm grasp on their quality.
My collection contains two 'pin holes' - unfortunately.

As to your stock, I believe the wood is original. I have a lifter with similar wood. There
is an easy way to possibly confirm its originality. Remove your right lock. During that
period (1870s), Powell's stockers would usually stamp their initials in the wood below
the front tip of the lock plate.