I don’t mean to be disagreeable, so I’ll agree that you got the handle glued back together again.
Learning to do restorations, especially repairing previous repairs, is a long and involved process, and on this one, you learned that using saw dust in the glue isn’t such a good idea because it simply results in a large, unbecoming, dark colored glue line.
Also, most guys doing a restoration on a handle like this would take extra care not sand away any of the old original finish, or the dents and scratches in the old wood. Sanding everything down like you did just insures that the handles of the two guns will no longer match one another as your pictures show.
As a suggestion, next time you try something like this, first try to fit the broken wood back together in such a way as the glue line will be all but invisible, and then use only a small amount of glue with no saw dust in it.
I agree it’s easier said than done, but that is generally what needs to be done.
John