Nice carbine as a starting point for restoration. The parts are available for doing a lot to restore this to "correct" but it will never be able to be "original". Collectors prefer "original" rifles and carbines but "correct" ones are valuable and collectible too because so few original ones are left to be collected.

I would actually, as stated, stick with the 1896 rifle sight. It will fit your carbine fine if you use the correct screws. I searched hard for an 1896 carbine sight a couple years ago and had no luck except one offer to sell me one for north of $600. I actually found one in an auction that was great and I stole it for a wonderful price because it had been mislabeled and I knew what I was looking for. (see "Search For The ’96 or A Tale of Two Carbines" in the articles section) The advice to learn from this forum and reading Poyer's or other references is invaluable.

So, good luck getting the restoration done. Take your time and you'll be glad you did down the road. Great way to keep a family heirloom alive and well!