Swedish - Carl Gustaf
Swedish license steel magazine markings.
"Crowned C" indicates it's made by Carl Gustaf Stads gevärsfaktori in Eskilstuna, Sweden.
The Swedish AK-4 was produced in the years 1965-70 by Carl-Gustaf Gevärsfaktori and Husqvarna vapenfabrik, and from then until 1980 when production ended it was made only by Carl Gustaf.
Husqvarna Vapenfabrik has previously used an "H" or "crowned H" to mark their products, but I'm not sure if there's any G3 parts marked in this way.
The Swedish also made an optional night sight for their AK4 depicted HERE.