Pictures of:
the serial number and any suffix on the front of the frame and on the slide;
the proof marks on both sides of the slide and frame
any other marks on the barrel, slide and frame; and
of the pistol over all so we can see it's entire configuration
would help an awful lot, since the devil is in the details with a Luger.

If you provide that, I can tell you what it is.

So far, you haven't shown much.

The crown N is a Nitrocellulose powder proof mark used on Lugers from 1906 until 1930 when DWM was acquired by Mauser Werke, and in total they produced about 1 million Lugers and 38% of all Lugers made through WWII.

The mark on the toggle is the DWM mark (Deutsche Waffen und Munitionfabriken).  DWM was the primary supplier of Lugers until 1930 and hey produced excellent quality military as well as commercial Lugers.

Luger small parts were marked with the last 2 digits of the serial number so the  "03" should be found on all the major small parts in the pistol.  Non-matching Lugers lose about half their value.

I believe the N means commercial.  Dwm is deutsch waffen and munitionfabriken. Usually the year is on the chamber strap with them  

As Dakota said we need more to give a proper determination