I can't say for sure on Daryl's sight, but I suspect it is a thick piece of silver with a peg rivetted and soldered to the steel base, in his case, and then filed into the bead shape. I always set the blade into a hole in the base, rivet over the bottom, file it flush, and silver solder everything together.
On an occasion when I was at a shot some distance from home, my Hawken slid sideways and landed on its side, bending the sight over flat against the barrel. I simply used a pair of pliers and bent it right back up straight again, and continued with the match.