The Ladder rear sight on the Pedersoli Sharps I saw, was a VERY poor 'rendition' of the original ladder sight. The spring (body design) did not work to hold the sight's ladder upright. Very sloppy. I bought one of those ladder sights from Brownells for my new Winchester Model 1876 & it's beautiful - even nicer than my original Sharps ladder sight that is on my modified 68.
I'll try to find the link for you - they retail $169.95? at Brownells - same price at Buffalo Arms, but the Brownell's sights are more nicely made with detents between range numbers for positive stops.

Here it is:

http://www.brownells.com/rifle-parts/sights/rear-sights/m-95-long-range-sight-prod18599.aspx