The "G" just means it is a former Romanian Civil Guard AKM. They were actually fully auto AKMs converted by the Romanians to semi only for the Civil Guard. They are pretty much 99% of the Romy kits now and very good quality.
ITM is synonymous with Ohio Ordnance Works. They are relatively good, budget receivers. I used one to build my Romy side-folder.
I believe Century marks theirs USA, but I am not sure. KVAR's trigger groups say "US" inside a circle. If it's a TAPCO trigger, "TAPCO" will be easily visible on the trigger itself, like this:
