Just in case anyone had any doubt remaining about whether there is an O-ring around the LED!
In fact, this shows it is better installed that I expected - there is a full groove for the O-ring. On the Sunwayman R01A, it is merely held in place in a shallow counterbore by the flange at the base of the emitter.
Great idea for the dead light, and nice work cleaning it up. I really like cutaways, even when it’s a simple item. There’s even a museum in my area that has an entire tank cut in half like this. I spent probably close to an hour studying it last time I was there.
Also, since I looked it up, here’s the SK68 cutaway post: