The info from the State Police clearly states you can carry any firearm YOU own, but not one owned by anyone else. So, yes, you need only qualify with one, instructor's discretion to list others, when I took the class, it was said he wasn't sure about adding one later when I asked about a 4th firearm, I had on order but not received.
I just got back from having prints done in PA this morning, Clerk said nothing about it. She was the one to tell me that see if they have walk ins available...and I went to Fairless Hills.