You should always runs Sigs wet IMHO Pay particular attention to the rails. Here is a great link and write up. This is a little less of an issue with the stainless steel framed guns but I would still run any Sig with this type of lubrication.
As far as care of a Nitron vs Stainless steel Sig it should be the same if they are current production. Stainless does not mean it cannot rust. If neglected it can and will rust....
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