I recognize the Sell style, relief carved rifle in the series of 'A+K' photos. It was, and probably still is, in California, as the writer suggests. The gun came out of the Bowers' collection, in PA, (Gunmakers of Pen-Mar-VA), and he had identified it as a Kleindinst made piece. Not sure why he came to that conclusion.
As to the rifle itself, it is a beautiful gun with nice carving that appears to have connections to the Sells. The original lock has been replaced with a large earlier style lock, and the fit is not particularily good. If you examine the sideplate, you can see that the forward part is discolored; that is where a new piece of brass has been scabbed on taking it all the way to the front of the sideplate shoulder. The front lock bolt hole was relocated forward to accommodate the replaced lock as well.
Bowers was primarily a furniture restorer and did beautiful work, mostly for the senior Joe Kindig. He also 'restored' guns and very likely did the lock work on this rifle. Probably done some 40 to 50 years ago, back when 'any old part would do' when it came to restoration.
This is a great subject: one which needs to be reconciled due to misinformation, and guess work, when initials are all we have to go on, if that. Thank you.
Dick