Legal in PA. By which I mean there is no law saying you can't but no law saying you can. Around Philly I've heard it is VERY looked down upon. As is having a knife on your person without needing it for your job. Here in PGH PA you can open carry and have pocket knives lol.
You only need the permit to conceal. You can open carry without the ccw. But once your shirt manages to get over that gun (or you enter your vehicle) your now conceal carrying, so getting the permit is always a good idea.