After removing about 3 lbs of cosmoline, it now looks like: an SKS.
There is some wood and finish wear, as shown, but internally all the parts look really good, with matching serial numbers on lots of them, I did not see any mismatched parts. The quality of the machined parts is quite good for a military rifle of this type. Must have been made when they weren’t shipping everything they could make-- just to foment some revolt or conflict.
Anyway, thanks for offering, this one will be a keeper, and just so I can say I have one.