I'd speak to a criminal defense atty or legal affairs network near you.
They can explain the gun & knife laws to you. As for printing, most uniformed cops or security officers who may see your M&P pistol may ask you for your valid CC license. If its a honest mishap or the wind I doubt you'll have trouble. Make a real effort to conceal your firearm if it's the PA law.
I toted a full size Beretta 96D with a extended stainless barrel in a Aker shoulder holster when I lived in west PA in the late 1990s.
For laws & SOPs, see;
www.nra.org www.knifelawsonline.com www.gunlawguide.com www.handgunlaw.us .
Be polite & don't dart around if you get pulled over. Calmly explained to the LE officer you have a valid carry license, then wait for the officer(s) to ask you if you are armed. Cops feel better if they decide what happens on traffic stops on their terms. You have civil rights too, if the officer or trooper is rude or unprofessional, file a formal complaint against them.
CF