New England Firearms is not a fly by night company. They make very fine quality firearms and their customer service is quite good. If you have an issue I'm sure they will do everything they need to to ensure they support their product.

Up to you but I would suggest at a minimum returning to your point of sale (Bass Pro Shops) and then:
A) Exchange it for another Sidekick. (My choice if I did not/could not spend any more money).
B) Have them (Bass Pro Shops)return it at their costto NEF for repair. I'm sure NEF will support their product.
C) Return it to Bass Pro Shops for a credit towards a T/C Omega in Blue/Syn for $299 or a Traditions Pursuit Pro Nickel/Syn for $269. My choice would be the Omega (I have two), but other than having a slightly heavy trigger (which Traditions will lighten for a fee) the Pursuit Pro (not the LT as it's too light)is a really nice balanced, handling and shooting ML.

BTW, you don't really need a stainless or nickel barrel so long as you properly care for your weapon. Even stainless and nickel will rust if neglected.

Tahquamenon