I believe your barrel was replaced in Weimar era, given the proof you show and also the "Weimar type" eagle below the barrel gage marking on the bottom.
The side plate first was on a commercial or early first Issue DWM luger, then re-used and re-numbered to the pistol, likely when the barrel was added during a re-work. It is pretty mixed up, but largely a 1911 DWM upper on a post 1913 Erfurt frame.
Trying to "figure" it out is tough, and my guesses above may be wrong- but it really does not matter much!
It is a shooter- if it shoots!
Welcome to the forum.