I would take the story with a grain of salt. 2000 degrees is quite hot certainly hot enough to remove the temper from the springs, so I don't imagine those mags were usable. What kind of shape is a soup can in after a trip through the campfire?
We live in a disposable society. There are few things we own or use today that will be treasured by our great grand kids. Glocks are perfectly good tools. Works of art to be treasured by generations, not so much. But to be honest, how many of our fore fathers guns are there to be treasured today? They were tools they were used and abused and traded for the next best thing to come along.
I don't think I would get to worried about where my Glock will be in 2115, or what quality of artifact it will be. Think of it as a hand saw, use it, treat it well, but when the teeth are worn get another.