Scourge Apprentice Emitter

I purchased the Customizable Apprentice Saber as a Christmas present for my son. It took about three weeks to arrive, so I was worried it might not make it in time for Christmas, but fortunately it arrived just in time.
My son was very happy with it and said the quality was exactly as amazing as he had hoped.
I chose the Scourge emitter, but when I screwed it fully onto the body, the activation button and the cutout on the emitter did not line up. I probably should have ordered the timing shims as well.
There were three black rubber O-rings included in the package, so I used them to adjust the alignment. I'm not sure if that is their intended use, though.

Scourge Apprentice Emitter