This is very likely. I'm under the impression that the amount of Soviet SKS rifles that escaped being sent to an armorer for refurbishment is little to none. With that said, rifles that were scarcely used due to where they were issued, such as to a prison guard or a police station, probably needed very little work done, if at all. This may be the where the majority of the non-refurbs come from: It was sent to Boris the armorer, Boris notices there's nothing really wrong with it, slathers some cosmoline and throws it in the "finished" pile. Since most of them were fairly well used somewhat roughly, that may be why there aren't a lot of non-refurbs around.
Just my two cents. Everyone knows what it's worth.