I think my local gun shop has a new GPR left hand. I'll likely be heading down there this week. But I believe its a .50 cal. The last time I was down there was a GPR on the used rack. Not sure if it was a flint or caplock. But I'm pretty sure it was a .54.
I could take some pics and send them to you. If you like it we can haggle and if we agree on a deal I can buy it.