Im a long ways away but if there is an issue maybe I can help. Im an armorer for the 3rd Gen along with the M&P's. If its too complex there is always S&W's warranty center. They have done some work for me in the past and its always been top notch.
I'd take it to Vance's, they have a gunsmith who does good work on Smith and Wessons. Just do not be in a hurry for it to be done, they have a backlog there on work.