I'd be a little concerned that testing the stock in below freezing temps might make it unfairly brittle. Other than that, I'm betting on the gun surviving.
Question... Why does the safety have to be functional? I agree that a safety is generally a good thing; but with a boltgun it's not really essential. It'd be like insisting that the safety works on a DAO pistol.
I own 2 firearms that were built with no "safety" (both are safe, they just don't have a "switch-thing" that makes them unshootable)