The 45/410 Survivor barrel comes with a bead front sight only, H&R will drill and tap the barrel for a scope rail, many here have had that done by H&R or by their local smith, the rear two mounting holes work great for the Williams WGRS peep sight. I don't recollect anyone putting a front sight on it, most use a red dot or scope on the scope rail, but I'd look at some of the shotgun sights that mount over the bead or a barrel band type sight.
Tim