Hi Ric,
The C. Beck s x s has two tangs that are tapered like willow leafs and completely parallel to each other and the bbls. The locks are not heavily angled to be "toed in" at the tails, so there is a pronounced shoulder as the lock panels meet the wrist.
Some s x s rifles have separate tangs that gracefully bend toward each other with a “pigeon toed” look (which I think is classy), but to do the Beck justice, the separate tangs should be parallel and willow leaf shaped.
For me, s x s American long rifles are best done with separate tangs and full stocks. The double hooked breech with one tang looks too "double barreled shotgun” for me, and I would expect to see that coupled with a rounded underside to the stock, a tapered half stock forearm, and no grip rail on the trigger guard. There certainly is a continuum of s x s American double rifles and combination guns (mostly original percussions), from full blown Kentucky rifle style (like the C Beck) to quite modern configurations with full round barrels, flat toes and butts, tapered short for ends, no grip rails, and Winchester type elevating rear sights, but at that end of the spectrum, I can’t call them Kentucky of American long rifles.
Bill Paton