If it were mine, I would take the recoil pad off and see if how far the crack goes, if it is a crack. On the one picture of the left lock the wood finger is not tight against the lock and I would be more concerned about that.
The gun looks in otherwise good condition. You didn't mention how long the barrels are. A 12 ga. Ideal Grade with ejectors in the same condition, a 16 ga. would bring 50% more.
The chamber length would be 2 9/16", 2 3/4" chambers came out in late 1939-40.
A nice gun for someone to add to their collection. Good luck with it and let us know how you make out.


David