Yeah that gun was posted in another area of the forum, the machine to do this is pretty much out of reach ($$$$$) to the home shop kind of people.
But this is the first I seen about the 500 round test, and it's actually unbelievable that it wasn't heat treated.
I'm going to link to this thread in the other one if I find it, and post that in here.
Here's the link to the other thread
First 3D printed 1911- in stainless