I dunno on the numbers deal, I would do a google search of your serial number with that last 2 numbers X'd out and rust(smith 111XX rust), just a guess... or maybe google M&P rust, and see what comes up, and if this is a well know issue, and what smith has been doing for people. Ill take a look into melonite and let you know what i find. I have heard of the stuff, but not really looked into it...