What you have is a very, very special rifle in your hands.
The early, non-model marked imports are difficult in themselves to find, but most are in 5.56/.223. I've only ever seen another early 7.62/.308 import such as yours, and it was in AR configuration.
You are correct in the assertion that it has a riveted ejector, a feature found only on the very first .308 Galil rifles made. You will also note that it has virtually the same receiver as the full-auto guns, and that the hole on the left side for the safety axis indicates this.
If you have more pictures of this model, we would all be very interested to see the rest of it, particularly the barrel. There is a small chance that you may have one of the sample guns as featured on the MR and AA catalogs that tend to have odd barrel lengths and other features that sets them apart from normal imports.