The first Darne guns were not sliding breech guns, but, around 1877 Regis Darne started working on perfecting the sliding breech Darne. Those early guns turn up, here and there, but, I wouldnt be in a hurry to make an old one a daily user.
I have had my real old guns experience, and, moved on.

Brent, once I saw that you made use of a Greener, with safety to the left, I quit worrying about the Darne safety working out for you. A Charlin has a safety that is difficult to move, sprung like a light truck, and I no longer chase those. Again, the lever on a Charlin makes a dandy safety, but, Im content with my Darnes.

Im glad you missed out on Liberaces Darne. I get queezy looking at it.

I wish you the best of luck. I cant say I know anyone who has actually completed a gun deal with James Wayne, but, I know a few people who have tried, and failed. If you end up with it, let us know.

Best,
Ted