They're very old, and were made as you see them.
The smooth finish is the result of the cut and polish as they were made.
Horn, antler, bone and ivory can all have a texture or be made smooth as a baby's behind.
Sturm, Ruger used four different suppliers for their stag grips, and they were only made until about 1962.
The identification of original/non-original stags is best done using the medallion-inletting and sanding marks on the grips' backsides for reference.
The literature refers to highly-polished and rough from the suppliers.
Stags and ivories were left-hand screwhead grips (like S&W), as opposed to right-hand screwheads on the wood grips.
Who made them?
Beats heck out of me. :lol: