Yes, Krag carbines occur in large blocks - we should be able to say yes or no with probably 95% accuracy. Measure the stock, if 30", it is more likely to be good, if 32", somewhat less so, but number will still tell an awful lot.

M1896C sights have been hard to find for many years. If the arm is well-used, someone might have taken the sight to complete a nicer looking specimen. While "wrong" to a purist, a 96R sight looks just fine from two feet away. But, the problem should be pointed out to the dealer - perhaps a lower price can be negotiated? I'm guessing the dealer probably bought it for a low price and may be trying to capitalize on buyer ignorance.