I may be wrong but I think it is just a piece of round brass rod that is drilled so it can be tacked down with brass escutcheon pins or finish nails. I donít think there is any weight on it. It is just there to keep the bottom of the door from swinging.
I donít think you actually need bronze in that application.
Square brass key stock should work as well and would be easier to drill. Maybe they use round to avoid the sharp edge on square stock.