New member- Questions about parts originality

[The lingerer]

Hello, happy to say I finally purchased my first luger last week, a 1938 S/42 matching russian capture bought at a gun show (perhaps not the best place to buy a first luger?)

From what I have read and understand, the germans moved away from strawing many of the small parts, including the trigger in favor of bluing in 1937. This is why I was confused to have a "light" colored trigger, although the numbers on the trigger match the rest of the gun.

Why is this? does this look like it may have been strawed? My best guess is that perhaps someone polished the trigger for whatever reason. In some places it looks like salt bluing remains, or perhaps this is preservative I was unable to remove or a tarnished portion.

Assuming it's polished, If I did salt blue it, would this be considered fraudulent, or returning the gun to original condition?

The bore is nice, but if this is an original all matching, should I refrain from shooting it or buy another toggle train for when I shoot it?

Finally, what is the deal with the upside down number in the sideplate?

Asking price was $1,200 and I paid $1,050 I realize value in russian captures is increasing, is this as good of a deal as I thought it was?

Thank you all in advance!