I'd say take the holster off. Most holsters have some metal in them, like snaps, and belt clips. That will set off the metal detectors. Then you will have to explain why you are wearing a holster for a gun in PA. WITH NO PERMIT, valid in PA.
This could make your trip to PA. a lost cause and a charge such as this could eliminate you from not Only getting a PA. permit, but bounce back on you here in Delaware and cause you to lose your DECCW.
Why go all the way there and screw it up at the last minute. Be safe and wise. Good luck.