Here is info from a gunsmith about the gun.

Yes the peep site is definitely added but looks pretty old(looks like brass screws). If appears not well placed/centered.

[img][img]https://i.postimg.cc/LYYpqDHd/0104-C771-4-A8-E-4-D1-F-A8-AD-DCE6-BC78-AC05.png[/img] [Linked Image from i.postimg.cc] [Linked Image from i.postimg.cc] [Linked Image from i.postimg.cc] [Linked Image from i.postimg.cc] [Linked Image from i.postimg.cc] [/img]