The finish that is scratched is just that, a finish. The tenifer is a metal treatment that you cannot see, you can completely strip the finish off your Glock and the tenifer is still there.
Tenifer is not a finish it is a salt-bath treatment to the metal itself making it extremely corrosive-resistant. The black finish that you say is wearing is just that... a finish. If you want the gun to be pristine and not have any wear, you should be able to have it re-finished, but rest assured if your Glock has a tenifer treatment to it, its still there.
However, I had a Glock Armorer tell me that Glock stopped using the tenifer treatment due to EPA regulations. Does anyone know if this is true? Also, does anyone know what they are using if the tenifer treatment is not being used now?
I took a tour once and watched them mold the lowers. It was very impressive.
The EPA has no say on what goes down in Austria. The manufacturing of parts needing the Tenifer finish are made in Austria then shipped to Smyrna, GA where the pistols are assembled. I believe that some frames as well as other internal parts (like triggers, springs, etc) are manufactured in Smyrna, GA. I took a tour once and watched them mold the lowers. It was very impressive.