I am going to review the threads and I will edit this post if/when I find the instructions.
Edit: Ok, I found this:
It looks like a strap wrench and hold the light upside down and push the reflector up into the flashlight while carefully watching for correct alignment.
I never bothered asking Neal to send me a smooth reflector. I just simply decided I wanted another GT94 for my other hand, and my second GT94 arrived with a smooth reflector.
One is a slightly smoother beam and a tiny bit more beam width and a tiny bit less throw, and the other is a slightly less smooth beam and a tiny bit less beam width and a tiny bit more throw.