Dutch Vickers questions
 

New to the board
Here are some pics of my Dutch pistol. I have a couple questions I could use some help on.
Can anyone tell me about the markings on the brass plate.?
I noticed the letter M next to and independent of the 2 number parts, is this typical.?
Also the C/16 on the right frame above the trigger and the C/15 on the right side of the breech block, what do they indicate.?

Thanks in advance for any insight I may receive

According to Martens & de Vries your unit marking indicates issue to the 2nd Garrison Battalion, West Coast of Sumatra (2e garnizoensbataljon Sumatra's westkust).

a few more pics
 

Thanks George for your time and info I really appreciate it.
here are some more pics of the same pistol