I replaced the reflector with a TIR lens in my SP40 to make it more floody.
Here’s a thread about it: Replaced optics in SP40 - mistakes were made
The reflector definitely isn’t glued. I didn’t see any glue on the bezel ring, but on my light it was very tight and only came off slowly after applying heat with a hair dryer. I have no idea how people are opening theirs with gloves and jar openers and whatnot. Needle nose pliers might be difficult to use, as someone said use circlip/snap ring pliers. If you’re going to take pliers to it maybe try heating the outside up first.
DC Fix seems like a common and effective mod for this light. More details in that thread, but I wouldn’t recommend trying to use a TIR like I did. The reflector is very small so you have to file down any TIR you put in there and you end up without enough room for the LED. I accidentally dedomed my LED in the process, but my SP40 still works great.