I just found another. If they were my photos, I'd post them. But it's just a pretty simple two-piece leather strap, with the rear piece buttoned on the butt, with no attached hardware. The forward end is like a belt end with holes. The upper piece is apparently sewn onto the forward swivel and has a plain buckle and leather keeper.
Nothin' fancy.
Personally, I do NOT like the buckle towards the front, as this is the part that hangs on my shoulder, or wraps around my arm when I'm shooting. If I have a sling buckle (I prefer actually to lace the sling together), I want it towards the rear.