Well since the receivers are identical, I see no reason why accessories wouldn't fit the CETME as well.
I bought mine back in Feb. so the ad copy and the weapons may have changed. Mine was brand new with a new barrel and not refinished, as was the CETME. Granted, used H&K parts are used for most of the internals, but they are still in good, functional condition. The G3 stock and handguard are American along with a few other parts to comply with the ban. The CETME's are wood and I don't know their orgin.
The only difference in the receivers are that the CETME has the flip up rear sight and the G3 has the H&K barrel sight.
These are really good looking rifles.