Yes, there is a gen 1, 2, 3.
This thread gives some insight:
I have seen a lot written about the differences in performance between the generations, but if you are looking at a used scope how can you know which gen. you have in your hands. I know that the turrets went from knurled to scalloped but I have seen some say that was from gen 1 to gen 2 and...
www.snipershide.com
Edit: Sorry I just realized that this wasn't your original question......my apologies. I would contact kahles customer or technical service on that.