Hello again, Robby !
"CN" stands for chrome nickel steel; of which the part that is stamped as such is made from.
"CV" stands for chrome vanadium.
"CW" and "CG" are other alloys, but the Bobba book does not say specifically what those alloys are.
The "encircled S" is an inspector's control mark.
The "rifle-N" stamp stands for the firm, SIG Neuhausen; who made parts for the Bern folks, usually the 1929 Bern frame.
If you find any luger take-down/screwdriver combination tools which are stamped with the Swiss federal cross at the gun fair this weekend, buy as many as you can and sell them to us here on the Forum. I will buy at least two from you !!! They are very rare to find here in the USA.
Finally, if you get a chance, you should really try to buy the book by Bobba. It will be invaluable to you as you continue to buy other Swiss lugers (which I have no doubt you will do...).
Following is a photo of my copy of my book just to show you what it looks like and my small, "starter" Swiss collection...
Regards,
Pete... <img src="graemlins/yltype.gif" border="0" alt="[typing]" />