I think I had the twin to this one in the 70's. Two piece stock, hardest piece of wood I've ever encountered on a gunstock.
IIRC mine had rifling that looked like it was done by rabid beavers. The triggerguard and buttplate looked sandcast.
Looks like this one got inletted and assembled to the point where it was usable, but the final sanding and finishing of metal and
stock never happened.