The hooks are by Rixen and Kaul and are used by other brands as well. The rivet-on railing is a good method for home-builders as well. The stiffening material on most Carradice bags is correx, corrugated plastic (like for-sale signs). You just rivet therough the canvas and correx and it holds for years.

My Carradice panniers are 10 years old and have survived a couple of scapes which would have melted nylon.