the only 'treatment' of the steel surface,before bluing;, is basically 'cleaning' and if needed, rust removal ( oxidation) but even this will be taken care of in the hot ,caustic, bluing solution ( bath) after , bluing is only "controlled oxidation...."
oh, and todays solutions are more of a black/blue, than the older ,'nitre blue'........many will say its just a 'black oxide" used by some companies. Ruger was using 'Dulites' formulas for their bluing operation........
the final "finish' will be determines by the "prep' done to the metal surface,polished, matted, etched in an acid bath ,etc....even bead ( sand ) blasting for a rough, matte finish.
Blued guns can and will last a LONG time, its the handling, wear and tear, cleaning, and of course any 'accidental' spills on the surface, including "body" fluids....blood, sweat & tears.............
more damage is done by "over cleaning" than anything else, except maybea "tight, leather" holster or leave it out in the elements.......