I was able to enlarge the photos and see that each side of the hammer has been milled down slightly.  To the point where the thin border edge on each side of the hammer knurling has been removed.  In doing so, the outside curve on the scallops has also been removed.

It also appears that the hammer has a lot of original case color.  If this is true, I’d say the milling was done at the factory, but why?

I’m wondering what that little symbol is below the serial number.

CJS57 said
The hammer is re-case colored among other issues. Those are not original Winchester colors or pattern.  

I don’t see any case coloring at all. Case coloring doesn’t have a pattern to it, as it is always random. If there is any color at all, it is merely from the heat of the friction of having turned the hammer down.

What I do see is where someone turned the hammer down a few thousandths. You can clearly see the circular motion cut into the metal, and if you look at that groove you can see where it was done unevenly, and done more than once.

I have no idea why anyone would need to do such a thing. 

Sincerely,

Maverick