I do believe that steel in guns is always harder than tempered Al. For what it is worth:
Al T6 Rockwell 60
Stainless Steel 70
I do believe that in the case of SIG, HK, CZ P series, etc., the Nitrocarbeurizing hardens it further. No, likely no chance of wearing out a P01. But, the hard anodizing adds an extra layer of protection and adds dimension to the metal on a SIG.
Also, when the P01 came out I do believe CZ mentioned something about the frame alloy that was an improvement over the PCR.