Many of the sights come with a base that will fit their dovetail, but is designed for round barrels.

Interesting about Jeff's - Cape Outfitters is where I bought my machine 'rough' Sharps Action. After draw-filing the milling marks off the action, action, I filed on the M68 hammer a bunch, converting it to more closely resembling a 'later' hammer.

There might just be a market for those actions today, if they can supply. I know I'd be interested in another for my 1867 Sharps Contract .50/70 barrel.