Interesting that Studebaker did not use heavy duty LOWER control arms on their R3-4 powered cars. (grease fittings on inner shafts instead of rubber)
They no doubt stocked these HD lower arms from left over '51-'52 production.
Actually, the easy answer is that they would have had to use the pre'58 front shock absorber setup, and they no doubt did not want to go back to that.