I have an older Centaur comp system, of which you pull back the slide, line up the holes, drop a paper clip in the hole, then release the slide, the clip keeping the spring assembly captive.
The one in the picture, I am not familiar with, but it looks like there is two holes, one in the plug and the other in the guide rod itself, as a guess, it looks like it would unscrew if rods were inserted into the holes.
The trouble is, red loctite may have been used in it's assembly and you may have to use heat, as little as possible, to loosen up the loctite.
Also look for clues when it was assembled, like slight deformations in those holes when it was tightened.
The top right picture looks like there was some possible damage from plier marks behind the plug.
Hopefully, someone familiar with that setup will come through for you, until then, best of luck.