silly question maybe

[VJJpunisher]

sorry if this is a stupid question and probably very elementary but my question is - How do you know what manufacturer made a Luger originally if the toggle has been replaced?

I've caught the luger bug and a local shop has a luger that seems to be two seperate guns, meaning all the numbers on the frame match each other but all the numbers on the toggle train (if thats the correct term) are different but match each other. The left side has the nitro stamp or the N under a crown which means its a commercial right? but the toggle has the 42 for mauser. The chamber area has 1920 stamped on it.

So how do I know what the original manufacturer logo on the toggle should be? thank you for any help clearing this up to my uneducated lugerness