Unusual markings on Chinese Type 56/SKS.

Bought this Norinco Type 56 yesterday, nothing particularly unusual about it, except the markings. Only a seven digit number, followed by 'G3', then 'NORINCA CHINA' and 'POLY USA, ATL GA'. First time I've seen both companies marked together like this. Also no factory triangle code at all. Any ideas on the 'G3'?

It looks like the "G3" was added when the import stamp was. I have no idea :confused:

I would bet that it is not part of the factory ser nr.
Some importers have done weird things with the way they marked their imports!
Sarge