I wish more guns were available for lefty shooters. I looked for years for an affordable production flintlock Kentucky rifle in a lefty flint. I never found it. I eventually got a used lefty percussion rifle that needed some stock work done.
I've shot righty percussion and will admit it actually is a do-able thing. The biggest issue I could find with the righty percussion was the spit of the cap onto my arm. I haven't bothered with a righty flinter-- didn't want to put down the money on something like that without knowing it would be a shootable gun for me.
I will also say I've seen Hershel House shoot a righty flinter left handed. So I guess some people do it, especially people who learned to shoot flinters back when just about everything was righty. There's been a lot of progress over the years for lefty guns: there was a time when you didn't shoot, write, eat, etc lefty handed. Everyone had to be righty. But there's still a long way to go-- I want to see a decent production flinter Kentucky type gun in a lefty. I've been disappointed over the years.