Thanks for the welcome. I'm on a bunch of boards and didn't know this one was here but got the word when I had a question about this pistol.
So, if the slot was welded then the finish could not be factory. However, I've got to tell you that all the maker marks and edges are sharp. I thought that whoever did it was smart as the sights are not nickeled. However, I misremembered and it was the hammer and safety that didn't get the finish. Such a finish would have been very appropriate in some locales.