Ken
to the forum! Ron has given you most everything you know. Yes I believe C.I.A. is Century International and is definately an import from the last 15 years or so.
You find the sidepaltes mismatched for the reason stated and other reasons too, but not really "common"...
history, well, made in 1942 for Mauser, served WW2, after the war was either russian capture or used by the east germans, then came to america.
You can do searches for byf 1942 on the forum and see what others have said too.
Ed