Exactly - as you can see, the wings at the rear, being held in a dovetail, are only guides. Sight itself is of 2 pieces, a spring that has a screw at it's front, holding it to the barrel, and the top swivelling piece that has the ladder, is hinged at the rear, between the 'ears'. This partcular sight is an original Sharps Carbine sight, as noted (I think I did) Even though it has a simple V rear notch, I routinely shoot 3 shot rest 1 1/2" groups @ 100meters with a 506gr.(Lyman mould) cast RN w/GC.

This smokeless load does 1,650fps from my .45 1.9" Sharps 35" bl. Using this roudimentary sigthing system, I was able to hit an orange steel plate 2 out of 3 shots at 228 yards, just over 200 meters. The plate was only 4 1/2" wide by 2 3/4" tall. Had it not been mostly orange it wouldn't have been visible to me - as it was just an orange dot. They are good hunting sights.
The one on my .45 Colt was very similar. I'm sure Winchester copied the Sharps sight, for their M86.
Browning or Pedersoli might be able to supply a sight. I think I bought the Winchester sight originally from Pedersoli, but aren't sure.