When the 339 came out Guitar Center had it on the front cover of their mail out little fliers quite a few times. So naturally I went over to the GC to check one out. Of course they didn't have one. That was how many years ago now, several anyway. I have been in that store a bunch of times since and I have never seen one. Maybe the larger GC's stock some of the high line Gibson stuff and guitars other than Les Paul models, but not here.
It's so hard to test drive a Gibson these days. When Gibson advertises their Dealer Days and I look at the list I don't remember there being any in Pennsylvania that host the event.