New to Lugers, Need some help ID'ing
 

Gentlemen,
Helping a coworker who inherited 2 lugers ID them. He is not a gun person and I offered to help. I was able to do some research on line but now am stumped. You seem to be a great resource so here goes.

1st one:
a DWM, but no 1918/1920 markings. Has a 3 didget serial number, with last 2 stamped on all parts.
Has what I can find out is a German "Nitro" mark on 2 places.
an "N" with a mark over it and what looks like a q or o stamped under the barrell. No other markins I have noted.

2nd one:
also a DWM but has 1918/1920 stamped on the receiver. has 8.82 stamped under the bbl, 4 proof marks on rt side of receiver and on the grip strap, ( 4/A.R. 5.51).

Thanks, Rob