I Hollis & sons double gun

I am not sure if this is the right place to post this, but I will give it a whirl. I have a I Hollis & sons double gun, it is a 12 gauge on one side and a 577/450 on the other. The rifle has a date of1873 as near as I can tell. I am looking for possible part replacement in the action and stock .I am not sure but it looks like it used percussion caps. The rifle has exposed hammers. The stock was broken in two at the wrist grip. The rifle is a family heirloom brought with them in the early 1900's I am hoping someone can tell some more info about this rifle. I will post photos as soon as I can. Thanks for any kind of help