One picture doesn't show me much, but if you just have surface rust, try rubbing with 0000 steel wool and gun oil. This alone can really make a difference sometimes and you won't get charged for it. It will not hurt the bluing. I use a product called Blue Wonder, thicker than oil and not so messy, often to enhance rusty guns to squeak out more dollars, and it will still be an "honest gun".
Bill
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