Sorry Tom, surface treatments are not my area either.
As a side note, the 7010-T6 alloys used are very high tensile strength and undergo an extensive heat treatment and quenching prior to machining the frame to remove any stresses, yada, yada, yada.... S&W patented the addition of a small amount of scandium into their alloys which helps somewhat, I'm sure but again, I'm no expert. Scandium is not a readily available element, it's pretty rare as it's only mined in Russia and China in limited quantities.
I would guess that the older Colt Commander frames were machined and lapped by highly skilled gun smiths and would definitely extend their usable life. Who knows how long my Para will last or any number of other frames out there but I would guess you would have to shoot the shit out of one before it let loose as a result of fatigue.
Drop the frame when you're cleaning it and it might break. I'm always careful with mine as the dust cover just looks too thin...