TIm, you're right... I keep forgetting that it's INDUSTRIAL age... so the quality is quite coherent.
As I have said, I'm most experienced in earlier weapons, where the style is much more important than the finish... because everyone had to buy one's own equipment from different smiths... My fault, I will try to remember.
I'd bet remnant of another part... serial numbers are mostly stamped paralell to a side, and mostly, if we're talking about a "stripe", on the centre area. It seems that there were numbers left out. This increases the chance of a copy.