Question and some further thoughts.
Ignoring the sanded checkering for a moment, what do you guys make of satin/oil finished wood on prewars? Does that necessarily imply refinish? Were all stocks given the heavier lacquer coat?
While on the subject of assessing M-12s (worth discussing!).....if you knew nothing else, you'd be somewhat suspicious of any "factory original" stock with so much figure in the wrist. And that observation applies to literally every firearm WW ever made - from lever guns on up the ladder.
And if you want to refinish a M12 or 21 receiver the very least you ought do is get the direction of filing correct.
But, for a decent price, that's still a nice M12 16.
Sam