Hi, just saw this thread. I can't speak for Dick but it's my understanding that yes, the rifle is or was in the holdings of the PA State Museum which is run by the PA Historic and Museum Commission (PHMC). That is the organization you'd need to contact to see if you can gain access to it, or if they have photos. I suspect any photos they may have are those that George Shumway took back in the late 70s. I'm not positive but I think it's been a long time since the rifle was displayed. It's been a long time since I was down to the museum, however, so I might be wrong.
You also might try giving a yell to Brad Emig - he may know something, as I believe he did some work for the PHMC a number of years ago.