Thanks again for your comments guys. Yes, I think that this is a Griffith's breech plug, and has been filed down from 1" to match the 15/16" barrel. The tang that came with the rifle was I think a home made affair but it was never going to work, so I replaced it.
Prospector, you have asked a valid question and I'm happy to explain my method of achieving that look. The cheek piece in this case should have been moved back about an inch, in my opinion, but with this short lop, it functions well where it is. A cheek piece of this style should appear to be applied to the surface of the buttstock. In order to get that look, one must pay very close attention to the plain of the wood from the butt plate forward to the wrist. It must appear to be a perfectly flat plain throughout the convex curve of the stock. There was way more wood when I got it that would allow this concept, so little by little, I filed it away with a Nicholson 48 or it's equivalent ( I call it jaws, it cuts so quickly), frequently holding the stock up to an incandescent light bulb to check the flatness, and watching down from above the comb to be sure I didn't go too far. Also, I laid a straight edge along the stock from the toe to the wrist to check the flatness of the stock. When I 'was there', I finished the radius of the outline of the comb with as rat-tailed cabinet maker's rasp, and reduced the comb to it's final height. Before I cut the highlight line around the comb, I sanded the wood to 220 grit and drew the arc in pencil as a rough outline I wanted. Then I used a fine 6" single cut mill bastard file to cut the line and accentuate the cheek piece. In truth, it didn't take very long, and the accent line really makes the cheek piece 'pop'.
Having sanded the wood to 220, I laid on a soaking of super saturated tannic acid and let it dry: that's as much powdered acid as will dissolve in hot water with agitation, and still will not dissolve it all. It turned the wood jet black when I laid on the ferric nitrate. When the FN dried, I blushed the FN with a heat gun and I sanded the wood back until I could see the light bars of wood between the black bars of the curl, with 220 grit paper. Around the accent line, I used the same file to back the paper, and a triangular shaped hard rubber backer for the rest of the stock. Then I repeated the staining, since it wasn't as bold as I thought I could achieve. Doing this process twice was the whiskering process, and once finished, I sanded the wood again with 320 grit. I wiped on another application of FN, let it dry, and blushed it again. This time, no more whiskers rose, so I simply burnished the stock with 0000 steel wool. The stock was finished with Circa 1850 Tung Oil Finish which I understand is made in Quebec. I slathered the oil on the wood which is a very satisfying job as the curl just looks fantastic. I let the wood 'take up' as much oil as it would, adding more as I saw dry spots, for about twenty minutes, then wiped it all off. I did this soak twice, allowing 24 hours between soakings for the oil to cure. After the second soak and dry, I applied oil on a folded two inch square of flannelette cotton, as evenly and thinly as I could...you don't want the oil to run. Always letting the oil cure for minimum 24 hours, sometimes several days, I repeated this for five applications. Then, with a maroon ScotchBrite pad, I cut away all the oil, right down to the wood. The SB pad was pretty aggressive, and the oil came off like dust. But I could see scratches from the pad, so again, I burnished the wood with 0000 steel wool. Now I used the flannelette cotton again, this time applying about half as much oil. As I added more oil each day, the finish went from flat to quite shiny, so when the forth application had thoroughly dried, I applied the final application, and rubbed it out with the palm of my hand.
Well, that's probably more than you asked for, but there it is.
A little more about the rifle - as I said, the barrel is 15/16" x .32 cal x 36" (including the plug). It weighs 8 pounds 14.5 oz. Daryl and I shot it yesterday to get the sights 'into the black' for the owner, but having achieved that, we quit before shooting a group 'for score' because of the cold. At -11 C our old hands can't take it anymore, and it isn't fun. I have never shot a rifle with that small a bore before, and was quite surprised that my usual .020" patch with LVL and the .311" ball was too loose a combination. Although the bore didn't 'foul out', it was far too easy to load and I think we'd have achieved better results with a heavier patch. We sighted it in with 30 gr. FFFg GOEX. and #11 CCI caps.
Here's a pic of my bro' and the rifle...