I depends greatly on what you are molding.
Is it abrasive (fillers)? Is it corrosive?
These will dictate mold materials.
Often parts that need a high gloss surface are made from harder mold materials.
If one face of the part requires the gloss then this is often an insert so that it can be removed and re-polished as needed.
Many die steels have stupid proprietary names so keeping them straight is a trick.