I also have a fifty-three caliber Sante Fe Hawken and a Palmetto Cal 52 steel mold, both bought at TOtW in the 1980's. The mold casts a 0.520" ball using my alloy: 98% lead (by volume, the ball weighs 98% of a pure lead ball).
The mold is a 2 cavity, fits Lyman handles, the cardboard box marked "REF. 520113" and "Italy." Although I purchased the rifle and mold at the same time, I know nothing about the name Palmetto and I've not seen any for sale since I bought the rifle. I'd be interested if anyone on this Forum knows the history of this item.