The chemistry history is not available which is unfortunate for the pebbletech warranty. However, the last company that serviced it are pretty good about maintaining balance, the only negative I could find was a CH of 250.
I would like to "treat" the features over time and maybe get the copper color back.
No! I love that patina color, and would leave them as is. Yes, copper would match the hues in your stone, but the green actually compliments the stone colors and adds visual interest to the scene. Plus, you don't have to do a thing to them, now or in the future. Design and color is my business/expertise, but I am quite lazy by nature. Take both into account when considering my advice!!