Rear Site replacement on 1917 Navy Luger

[barr44]

I have an old 1917 Navy Luger that for whatever reason has had the rear site removed from the back toggle.
I am wondering how one might replace the back site on a Navy Luger. I can't see any thing that indicates how the rear site would
have been attached. I do see the grooves on each side of the rear
toggle assembly, but don't see anything that would indicate how the site would have been held in place.
I have another 1917 Navy Luger, but I don't see anything that would indicate how the site is attached. It will slide back and forth when the side button is depressed, but comes to a hard stop when in the full back position.
I have another rear Navy toggle with the site coming in the mail and plan on trying to remove the site from it and putting it on my Navy, since my Navy has mostly all matching numbers.
If any one has any ideas as to how to remove one of these sites and
place it on another toggle assembly, I would appreciate any info forth coming. Thanks barr44
coming.