The original 1873 Rifle I used to own had a front sight in which the steel base/dovetail tapered up into an integral blade. And the upper 1/3 or so of that blade was German Silver, apparently cast onto the base. Back then I had an '86 short rifle with the same front sight. I'm pretty sure it was a factory standard, or at least an option.
The skinny blade topped by a brass bead is something from the early 20th Century, possibly a Marbles original design. I know they made it popular but I don't think it was original to the '73.
Dave