Just go to Flashlight-forums.com and get a bezel from RPM. He makes them from time to time. I believe he did the fabrication for this light. I'm sure Charlie has no parts left to sell for this light.
If you don't find an original replacement head, I have a series of heads that I made for the Cubs that will allow the use of a removable bezel. I have them in brass and aluminum with various milled cuts or knurled. I also have bezels available now in stainless steel (Ti bezels are nearly complete) You can use the original IMS-20 reflector or upgrade to a McR-20. You will need a larger diameter lens (22.8mm) with my bezel head. In addition, I also have battery bodies. PM for more info